EP3507505A1

EP3507505A1 - Pneumatic control system

Info

Publication number: EP3507505A1
Application number: EP17768964.3A
Authority: EP
Inventors: Norbert Fortmann; Tim Warning; Florent Orget
Original assignee: Aventics GmbH
Current assignee: Aventics GmbH
Priority date: 2016-08-31
Filing date: 2017-08-21
Publication date: 2019-07-10
Anticipated expiration: 2037-08-21
Also published as: CN109844326B; WO2018041284A1; KR102156503B1; DE102016010481B3; CN109844326A; KR20190031529A; US10760318B2; US20190194998A1; EP3507505B1

Abstract

The invention relates to a pneumatic control system for a working cylinder, which pneumatic control system enables resistance-free manual motion of the device driven by the working cylinder in the event of a failure or switch-off of the compressed air supply and is independent of electrical supply. The problem is solved by means of a pneumatic control system having a double-acting working cylinder (1), the two chambers (3, 4) of which can be connected oppositely to a compressed air source and a compressed air outlet (11, 11') by means of a controllable supply device having two operating positions, an independently resetting 3/2-way valve (13, 13') switchable by means of a control pressure being arranged before each chamber (3, 4) in a connecting line (5, 6) to the supply device, which 3/2-way valves connect the chambers (3, 4) to bleeding outlets (16, 16') in a first switching position and to the supply device in a second switching position, and a parallel circuit of a check valve (21, 21') and a throttle point (22, 22') being arranged before each chamber (3, 4), the check valves (21, 21') of which parallel circuits block in the backflow direction, wherein the two 3/2-way valves (13, 13') assume the first switching position in the idle position and can be switched by means of a common control line (18), which is connected to both connecting lines (5, 6) to the supply device downstream of the 3/2-way valves (13, 13') by means of a changeover valve (19), and the parallel circuits are arranged in the connecting lines (5, 6) downstream of the respective 3/2-way valves (13, 13').

Description

Pneumatic control

Technical area

The invention relates to a pneumatic control for a working cylinder, for example, to control the opening and closing of the doors of the

Passenger transport vehicles, such as buses, trams or trains. State of the art

For vehicle door control in the field of public transport, such as buses, trams or trains trains the use of pneumatic or electro-pneumatic controls is known. The controller includes as a drive one or more pneumatic working elements with pressure chambers for generating a

Opening and / or closing force for the vehicle door. As a rule, the vehicle door is associated with two pressure chambers, an opening chamber and a closing chamber. Here, as a drive, for example, a double-acting working or actuating cylinder can be used. To open or close the doors is the respective

Pressure chamber of the working or actuating cylinder pressurized and the other chamber vented. Operational safety considerations and statutory provisions also require the possibility of manual emergency operability of the vehicle doors in the event of faults.

From DE 32 25 536 AI a pneumatic vehicle door control with a double-acting working cylinder and an electro-pneumatic control device is known, whose chambers via upstream electrically switchable 3/2-way solenoid valves in each case in opposite directions with a compressed air source or venting outputs

Bestätigungskopiel the 3/2-way solenoid valves are connectable. The opening of the chamber upstream 3/2-way solenoid valve can via a hand-operated emergency valve, a shuttle valve and an additional ventilated by the compressed air source chamber from the loading in the

Venting be switched. For complete bleeding of the system, if necessary, the other 3/2-way solenoid valve can be electrically switched simultaneously to the venting state. The DE 32 25 536 AI disclosed pneumatic control also provides electrical safety circuits of the 3/2-way solenoid valves according to the differential pressure principle, if at certain points of the system due to operational disturbances defined pressure range are exceeded. The provided according to DE 32 25 536 AI emergency shutdowns require complete ventilation of the

Depending on the current operating state either an active circuit of participating members via a hand-operated emergency valve or additionally via an electronic switching device. The controller thus does not allow a complete automatic

Ventilation of the working cylinder in the event of failure or shutdown of the compressed air source, furthermore, a complete ventilation in case of failure of the electrical supply is not guaranteed. In addition, provided by DE 32 25 536 AI vehicle door control due to the large number of provided

Emergency shutdown functions relatively complex. DE 34 20 631 AI discloses a pneumatic vehicle door control with a double-acting working cylinder whose chambers are connected via upstream 3/2-way valves respectively opposite to a compressed air source or venting outputs of the 3/2-way solenoid valves. The two 3/2-way valves are over three

different electromagnetic, pneumatic and mechanical controllable

Actuators switchable. For emergency control, a third, electromagnetically switchable 3/2-way valve and a hand-operated emergency valve are provided. The

Control of the electromagnetic actuators via a central electronic switching device. The proposed by DE 34 20 631 AI vehicle door control sees - comparable to DE 32 25 536 AI - several relatively complex

Emergency shutdown functions before, by trained as a differential pressure switch monitoring devices or by manual operation by a switch or the Emergency valve can be set in motion and therefore has the same disadvantages as the vehicle door control known from DE 32 25 536 AI.

DE 196 457 Ol AI discloses a pneumatic door control with a double-acting working cylinder whose chambers via upstream pneumatically switchable 3/2 way valves each in opposite directions with a pressure medium inlet or a

Pressure medium outlet can be connected, wherein the switching of the two 3/2-way valves via three electrically switchable solenoid pilot valves takes place. The pneumatic door control provides a safety switching state in which both chambers of the working cylinder via a corresponding equality of the 3/2-way valves are connected to the pressure medium inlet and acted upon simultaneously by the operation of one of the three solenoid pilot valves, whereby an assumed position of the vehicle door is secured. The disclosed by DE 196 457 01 AI door control does not provide simultaneous ventilation of both chambers of the working cylinder. Furthermore, a failure of the electrical supply leads to failure of the controller, causing the

Working cylinder remains in its current operating state.

From DE 10 2008 01 1 315 AI a pneumatic vehicle door control is known with a double-acting cylinder whose chambers above upstream

pneumatically switchable 3/2-way valves are connected to a compressed air source, the 3/2-way valves connect both chambers in a rest position with the compressed air source and the control pressure for one of the two 3/2-way valves emanates from the pressure of the other chamber of the working cylinder. In one embodiment, the 3/2-way valves are resiliently biased in the rest position. In order to prevent a sudden opening and closing of the doors, the chambers of the working cylinder upstream of the 3/2-way valves each upstream of parallel circuits of the backflow blocking check valves and throttles, which act as exhaust throttle. The disclosed by DE 10 2008 01 1 315 AI vehicle door control sees no manual emergency operation of the vehicle doors with a venting of the chambers of the

Working cylinder in case of failure. DE 201 1 001 003 AI discloses a pneumatic vehicle door control with a double-acting cylinder whose chambers are connected via upstream electrically and manually controllable 3/2-way valves with a compressed air source, the 3/2-way valves both chambers in a preferably spring-loaded

Rest position pressurize and the working cylinder in the of him

secure position. The 3/2-way valves can be brought by electrically controllable actuators or by manual operation in a venting position in which their respective assigned chamber is vented, causing an opening or closing of the vehicle doors is effected. To a sudden opening and

Closing the doors to prevent the chambers of the working cylinder upstream of the 3/2-way valves each parallel circuits of the backflow blocking check valves and throttles upstream, which act as exhaust throttle. In the event of a break in the electrical power supply, the controller sees in DE 201 1 001 003 AI a manual emergency operation of the vehicle doors upstream by the manual transfer of a compressed air source upstream

Manual valve in a venting position, in which the system separated from the compressed air source and actuated by a by the manual valve with

Shuttle valve is connected to a quick exhaust, whereby both chambers are vented. The provided according to DE 201 1 001 003 AI vehicle door control requires the complete ventilation, the operation of a manual valve, which may not be reached in any emergency. The control also does not allow complete automatic bleeding of the working cylinder in the event of failure or shutdown of the compressed air source. Since the acting as exhaust throttle

Parallel circuits are directly upstream of the chambers of the working cylinder, they also act in manual emergency operation, which is an increased opening or closing resistance in manual emergency operation.

Disclosure of the invention

The invention is based on the object to avoid the disadvantages shown. In particular, an automatic full emergency ventilation is to be provided in a usable for controlling vehicle doors pneumatic control, which in the event of failure or shutdown of the compressed air supply a resistance-free manual movement of a power driven by the cylinder device, such as vehicle doors, allows and is independent of an electrical supply.

The object is achieved by a pneumatic control according to claim 1, advantageous embodiments are described in the subclaims.

The invention consists in the core of a pneumatic control with a double-acting cylinder, the two chambers via a controllable

Supply device with two operating positions in each case opposite to a compressed air source and a compressed air outlet are connected and each chamber in a connecting line to the supply device in each case a self-resetting, with a control pressure switchable 3/2-way valve is arranged, which connect the chambers in a first switching position with venting outputs and connect in a second switching position with the supply device, and each chamber is preceded in each case by a parallel circuit of a check valve and a throttle point blocking the check valves in the return direction, the two 3/2-way valves occupy the first switching position in the rest position and a

common control line are switchable, which is connected downstream of the 3/2-way valves via a shuttle valve to the connecting lines to the supply device and the parallel circuits are arranged in the connecting lines respectively downstream of the 3/2-way valves. The supply device is connected via connecting lines with the two chambers of the double-acting cylinder. It connects the chambers of the double-acting cylinder in two operating positions each opposite to a compressed air source and a compressed air outlet and thus ensures depending on the operating position for the pressurization (ventilation) of one and the simultaneous venting of the other chamber of the double-acting cylinder. By the opposing loading and venting of the chambers in the two operating positions each changes, driven by the working cylinder device with the respective direction of movement of the piston stroke in two different directions is movable, so for example, driven by the working cylinder vehicle doors can perform a closing and opening movement. To enable manual emergency operation in case of failure or failure Disconnection of the compressed air supply is arranged in the two connecting lines between the supply device and the chambers of the working cylinder respectively an automatically resetting, 3/2-way valve, which are switchable via a common control line downstream (ie in the direction of the supply device) of 3/2 -Wegeventile via a shuttle valve with two connecting lines to

Supply device is connected. The 3/2-way valves connect the chambers in a first switching position with venting outputs and in a second switching position with the supply device, wherein they occupy the first switching position in the rest position. As a rest position that switching position is referred to in the context of the invention, which occupy the 3/2-way valves due to their automatic reset, if they are not acted upon by a control pressure. Since the 3/2-way valves via the common control line and a shuttle valve with both

Connecting lines are connected to the supply device, they are always acted upon at their control inputs in both operating positions of the supply device with pressure, as long as the supply device via one of the two

Connecting lines provides a pressure. Here they are in their second

Switching position held in which they are the chambers working cylinder with the

Connect supply device. The chambers of the double-acting working cylinder are alternately acted upon in each case according to the two operating positions of the supply device (and the corresponding chamber in each case via the

Supply device vented). If the supply of compressed air provided by the supply device fails or is switched off, this also results in a loss of the

Control pressure at the control inputs of the two 3/2-way valves result. The 3/2-way valves fall due to their automatic reset in the rest position and thus take the first switching position in which they the chambers of the

Connect working cylinder with venting outlets. Thus, the double-acting cylinder is completely vented in this state and driven by him device can be moved without resistance in both directions of movement manually. The manual emergency operation is ensured by purely pneumatic means and is independent of the existence of an electrical supply. The pneumatic control according to the invention provides at the same time that the chambers each upstream of parallel circuits of check valves and throttle bodies, the check valves in Block reverse flow direction. The two parallel circuits each have the function of an exhaust throttle, as it is basically known for example from DE 10 2008 01 1 315 AI. When pressurizing a connecting line through the supply device opens the respective check valve and gives access to the respective chamber of the working cylinder over the full cross section of the

Connection line free. In the return flow direction, that is, when the respective chamber is compressed, locks the check valve, which is why the exhaust air from the chamber only over the reduced throttle cross-section of the throttle point in the direction of

Supply device can escape. As a result, a back pressure builds up above the throttle point, which counteracts the piston movement. The piston stroke is braked, whereby a sudden movement of the device driven by the working cylinder, for example a sudden opening and closing of connected vehicle doors, is prevented. In deviation from the DE 10 2008 01 1 315 AI, however, the exhaust throttle in this embodiment does not interfere with the manual emergency operation. By the parallel circuits not directly upstream of the chambers of the working cylinder, but are arranged in the connecting lines in the exhaust direction only downstream of the 3/2-way valves, the displaced from the chambers by the piston movement in the event of a failure or shutdown of the compressed air supply via the vent exits then the 3/2-way valves are in the rest position each escape over the full cross-section of the connecting line. The invention has recognized that with the illustrated control, a pneumatic control for a double-acting cylinder is provided with exhaust air throttling, in a simple way, an automatic, resistance-free manual emergency operation is possible with purely pneumatic means.

To regulate the damping effect of the exhaust throttle, the throttle points are each formed with an adjustable throttle.

The automatic reset of the 3/2-way valves is structurally easily achieved by biased spring-loaded at rest. In a compact design, the controllable supply device with the required properties is formed by a pilot operated 5/2-way valve. The 5/2-way valve has two working ports for connection to the two

Connecting lines to the two chambers of the double-acting working cylinder and a compressed air connection for alternately pressurizing the working connections in the two operating positions and two compressed air outlets to connect the respective unoccupied working connection with the atmosphere for venting.

In an alternative embodiment, the controllable supply device of two pilot operated 3/2-way valves is formed, each having a working port for connection to a connecting line, a compressed air connection and a

Have compressed-air output and which are so synchronously pilot-controlled as common means that in two switching positions alternately one chamber of the double-acting working cylinder with a compressed air source and at the same time the other chamber with a compressed air output is connectable.

In the above embodiments, the damping caused by the parallel circuits during operation acts on the entire piston movement in each case. However, the damping can also be configured only as Endlangendämpfung by the chamber of the respective pressurized chamber opposite is vented in an initial section of the piston travel in addition via a further opening, line or another output. This can, for example, as an integrated into the cylinder

Endlagendämpfung be configured by the piston of the working cylinder or formed with the piston damping approach in the end-position sections additional, arranged in the chambers of the working cylinder, connected to the atmosphere

Venting channels seals, as is known for example from DE 33 45 631 AI.

In a particularly compact embodiment of the pneumatic control with an integrated cushioning both chambers are formed with additional, each at the beginning of an end portion of the piston travel radially arranged vents, which each chamber via vent lines with

Check valves downstream of the parallel circuit with its associated Connect connecting cables. In this case, the respective compressed chamber is vented in each case via an initial portion of the compression movement of the piston in addition to the vent via the throttle point via the vent opening. As soon as the piston overflows the vent opening when it reaches its position, it seals it circumferentially. From reaching this position, the respective compressed chamber in the rest

End portion of the piston movement only vented through the throttle point, which dampens the piston movement until reaching the end position. The length of the throttle path is in a structurally simple manner by the axial position of the

Vents on the way of the piston determinable. In

Return direction, that is, when the respective supply line, lock the check valves respectively.

Advantageous developments of the invention will become apparent from the

Description of a preferred embodiment of the invention shown with reference to FIG. It shows:

Fig. 1 is a schematic diagram of a pneumatic according to the invention

Control. According to FIG. 1, a pneumatic control according to the invention has a pneumatic drive designed as a double-acting working cylinder 1. The double-acting cylinder 1 is used to open and close a vehicle door, not shown in Figure 1 by the movement of the piston 2. The two chambers 3 and 4 of the working cylinder 1 are connected via connecting lines 5 and 6 with the

Electromagnetically piloted 5/2-way valve 7 trained supply device connected. The 5/2-way valve is pre-controlled via the electromagnetic pilot control device 8 and has two working ports 9, 9 'for connection to the two connecting lines 5 and 6 to the two chambers 3 and 4 of the double-acting working cylinder 1, and a compressed air connection 10 and two compressed air outlets 1 1 and 1 1 '(exhaust air outlets). The 5/2-way valve 8 is biased in accordance with the illustration Figure 1 with a spring device 12 spring loaded in a designated as rest position first operating position in which the connecting line 6 to the compressed air connection 10 is connected. In the two connecting lines 5 and 6, the chambers 3 and 4 downstream of each with a control pressure switchable 3/2-way valves 13 and 13 'upstream. The two 3/2-way valves 13 and 13 'each have a first

Connection 14 and 14 'for connection to the chambers 3, 4 and a second connection 15, 15' for connection to the working ports 9, 9 'of the 5/2-way valve 7. Furthermore, 3/2-way valves 13 and 13 'vent exits 16, 16' on. The pilot control of the 3/2-way valves 13 and 13 'via the control terminals 17, 17' and the common control line 18. The control line 18 receives the control pressure via the shuttle valve 19 and the connecting lines 5, 6 downstream of the 3/2-way valves 13th and 13 'of the working ports 9, 9' of the 5/2-way valve 7. The 3/2-way valves 13 and 13 'have two switching positions, wherein they according to the illustration Figure 1 each with a spring means 20, 20' spring-loaded in a biased as the first switching position are biased in which the chambers 3 and 4 of the working cylinder 1 with the venting outputs 16 and 16 'are connected. In the connecting lines 5, 6 are downstream of the 3/2-way valves 13 and 13 'and upstream (that is, in the direction of the chambers 3, 4) of the branches of the

Connecting line sections 5a, 6a to the shuttle valve 19 each parallel circuits of check valves 21, 21 'and adjustable throttle bodies 22, 22' are arranged, the check valves 21, 21 'in the return flow direction - that is, downstream - block. The chambers 3, 4 are formed with respective radially arranged at the beginning of an end portion of the piston travel vents 23, 23 ', the chambers 3, 4 respectively via vent lines 24, 24' with check valves 25, 25 'downstream of the parallel circuit with the sections 5a, 6a connect the connecting lines 5, 6. The compressed air connection 10 5/2-way valve 7 is manually by means of manually operated emergency valve 26 either via the working port 27 to the compressed air connection 28 (which is connected to a compressed air source not shown in FIG. 1) or the

Venting port 29 connectable.

The pneumatic control shown in Fig. 1 operates upon application of compressed air as follows: The emergency valve 26 is open, which is connected via the compressed air port 10 via the working port 27 and the compressed air port 28 of the emergency valve 26 to a compressed air source. Is the 5/2-way valve 7, according to the Representation in Fig. 1, in its first operating position, which at the same time his

Rest position is, the compressed air connection 10 is connected to the working port 9 '. About the connecting line 6, the shuttle valve 19 and the parallel

Check valve 21 'acted upon. The shuttle valve 19 opens due to the

Pressurization via the branch 6a of the connecting line 6, whereby the control line 18 is acted upon and both 3/2-way valves 13 and 13 'via the control terminals 17, 17' from the first switching position (the biased rest position) against the bias voltages of the spring means 20, 20th 'each in their second

Switch position to be moved. In this second switching position, the first terminals 14 and 14 'are connected to the second terminals 15, 15'. About the connecting line 6 opens due to the pressurization, the check valve 21 '. About the open 3/2 way valve 13 ', the chamber 4 of the working cylinder 1 is pressurized (vented). As a result, the piston 2 moves from the chamber 4 in the direction of the chamber 3 and a vehicle door driven by the working cylinder 1 opens. The chamber 3 is in an initial portion of the movement of the piston 2 over the

Vent opening 23, the vent line 24, the connecting line section 5a, the connecting line 5, the working port 9 and in the first operating position of the 5/2-way valve 7 connected to this compressed air output 1 1 vented, the check valve 25 opens due to the pressurization. At the same time the chamber 3 is vented in this section of the movement of the piston to a lesser extent via the control line 5 and the opened 3/2-way valve 13, wherein the check valve 21 blocks and air through the throttle body 22 and in the

Connecting line 5 is delivered to the working port 9. As soon as the piston 2 passes over the vent opening 23 arranged at the beginning of the end section of its movement, it seals the latter circumferentially, so that no air escapes from the chamber 3 via the vent opening 23. From this point on the movement of the piston 2, the chamber 3 is vented exclusively via the control line 5, the opened 3/2-way valve 13 and the throttle point 22. Due to the delayed emptying over the narrowed cross-section of the throttle point 22, the pressure in the chamber 3 acts as a back pressure, which dampens the movement of the piston 2 in the end position portion and thus the opening movement of the vehicle door. If the 5/2-way valve 7 is moved by the electromagnetic pilot control device 8 against the bias voltages of the spring device 12 in its second operating position, the compressed air connection 10 is connected to the working port 9. About the

Connecting line 5, the shuttle valve 19 and the check valve 21 are applied in parallel. The shuttle valve 19 opens due to the pressurization via the portion 5a of the connecting line 5 in the opposite direction, whereby the control line 18 is acted upon by the connecting line 5, 5a and both 3/2-way valves 13 and 13 'via the control terminals 17, 17' against the bias voltages the spring means 20, 20 'are each moved to their second switching position. The chamber 3 of

Working cylinder 1 is pressurized via the open 3/2-way valve 13 and the connecting line 5 (vented). As a result, the piston 2 moves from the chamber 3 in the direction of the chamber 4 and a vehicle door driven by the working cylinder 1 closes. The chamber 4 is in an initial portion of the movement of the piston 2 via the vent opening 23 ', the vent line 24', the connecting line section 6a, the connecting line 6, the working port 9 'and in the second

Operating position of the 5/2-way valve 7 vented with this connected compressed air outlet 1 1 ', wherein the check valve 25' opens due to the pressurization.

At the same time the chamber 4 is vented in this portion of the movement of the piston to a lesser extent via the control line 6 and the opened 3/2-way valve 13 ', wherein the check valve 21' locks and air through the throttle point 22 'in the connecting line. 6 is delivered to the working port 9 '. As soon as the piston 2 passes over the vent opening 23 'arranged at the beginning of the end section of its movement, it seals it circumferentially, so that no air escapes from the chamber 3 via the vent opening 23'. From this point on the movement of the piston 2, the chamber 4 is still exclusively via the control line 6, the open 3/2

Directional valve 13 'and the throttle point 22' vented. Due to the delayed emptying over the narrowed cross-section of the throttle body 22 ', the pressure in the chamber 4 acts as a back pressure, which dampens the movement of the piston 2 in the end position portion and thus the closing movement of the vehicle door. The sealing effect of the piston 2 with respect to the ventilation openings 23 and 23 'is improved by being formed at its two ends with seals, for example circumferentially arranged sealing rings. The illustration Fig. 1 shows the pneumatic control in its venting position, in which the vehicle door driven by the working cylinder 1 manually moves without resistance (open or closed) can be. No air pressure is provided via the compressed air connection 10 because it is switched off via the emergency valve 26 in that the compressed air connection 10 is connected via the working connection 27 to the ventilation connection 29 of the emergency valve 26. In this position, no air pressure is provided regardless of the operating position of the 5/2-way valve 7 via the working ports 9 and / or 9 '. As a result, the control line 18 and the control terminals 17, 17 'of the 3/2-way valves 13 and 13' are not pressurized. The 3/2-way valves 13 and 13 'are due to the bias of the spring means 20, 20' respectively in their first switching position, the rest position. In this first switching position, the first terminals 14 and 14 'of the 3/2-way valves 13 and 13' each with the

Venting outputs 16, 16 'connected. Both chambers 3, 4 of the working cylinder 1 are completely vented through the venting outputs 16, 16 ', without that in the

Movement displaced air must pass through the cross-sectional constrictions of the throttle bodies 22, 22 ', since these are arranged only downstream of the 3/2-way valves 13, 13'. The piston 2 can be moved without resistance from the chamber 4 in the direction of the chamber 3 or in the opposite direction and the vehicle door can be easily opened or closed. The same behavior is reflected in a failure of the compressed air supply regardless of the position of the emergency valve 26th

W

14

LIST OF REFERENCE NUMBERS

1 working cylinder

2 pistons

3, 4 chamber

5, 6 connecting line

5a, 6a connecting line section

7 5/2-way valve

8 pilot control device

9, 9 ', 27 work connection

10, 28 Compressed air connection

1 1, 1 1 'compressed air outlet

12, 20, 20 'spring device

13, 13 '3/2-way valves

14, 14 'first connection

15, 15 'second connection

16, 16 'vent outlet

17, 17 'control connection

18 control line

19 shuttle valve

21, 21 ', 25, 25' check valve

22, 22 'throttle point

23, 23 'vent

24, 24 'vent line

26 emergency valve

29 exhaust port

Claims

claims

1. Pneumatic control with a double-acting cylinder, the two chambers are connected via a controllable supply device with two operating positions respectively opposite to a compressed air source and a compressed air outlet and each chamber in a connecting line to

Supply device is arranged in each case a self-resetting, with a control pressure switchable 3/2-way valve, which connect the chambers in a first switching position with venting outputs and connect in a second switching position with the supply device; and each chamber one each

Parallel connection of a check valve and a throttle point is upstream block the check valves in the return flow, characterized in that the two 3/2-way valves (13, 13 ') in the rest position occupy the first switching position and via a common control line (18) are switchable the downstream of the 3/2-way valves (13, 13 ') via a shuttle valve (19) with two connecting lines (5, 6) is connected to the supply device and the parallel circuits in the connecting lines (5, 6) respectively downstream of the 3/2 Directional valves (13, 13 ') are arranged.

2. Pneumatic control according to claim 1, characterized in that the

Throttling points (22, 22 ') are each formed with an adjustable throttle.

3. Pneumatic control according to claim 1 or 2, characterized in that the

3/2-way valves (13, 13 ') spring-loaded in the rest position are biased.

4. Pneumatic control according to one of claims 1 to 3, characterized in that the supply device is formed from a pilot operated 5/2-way valve (7).

5. Pneumatic control according to one of claims 1 to 3, characterized in that the supply device is formed from two pilot operated 3/2-way valves, which are each associated with a chamber (3, 4). Pneumatic control according to one of claims 1 to 5, characterized in that the respectively pressurized chamber (3, 4) opposite chamber (3, 4) is additionally vented in an initial section of the piston travel via a further opening, conduit or another outlet.

Pneumatic control according to one of claims 1 to 5, characterized in that both chambers (3, 4) with additional, each at the beginning of an end portion of the piston travel radially arranged vent openings (23, 23 ') are formed, which the chambers (3, 4 ) in each case via vent lines (24, 24 ') with

Check valves (25, 25 ') downstream of the parallel circuit with its associated connecting lines (5, 6) connect.