HK1059071B - Bobbin cradle and operating vale for regulating the same bobbin cradle - Google Patents

Description

Creel device and control valve for a creel device

Technical Field

The invention relates to a creel which is pivotably mounted by means of a four-bar linkage on a support which is arranged on the frame of a textile machine and forms the fixed bar of the four-bar linkage, and which can be pivoted from a lower loading position into an upper operating position by means of a pneumatic cylinder which is articulated on one side on the support and on the other side on the movable bar of the four-bar linkage.

Background

As the name implies, a four-bar linkage consists of a mechanism interconnected by four bars, one of which is mounted stationary, while the other three are able to perform the required rotation or oscillation, depending on the chosen size of the respective bar.

In the creel described in FR 2794136a1, a pneumatic cylinder is provided which receives compressed air at one end. In order to move the creel with at least one feed bobbin into the upper working position, the pneumatic cylinder receives or receives compressed air in such a way that the piston rod is moved out of the pneumatic cylinder. Furthermore, a spring is provided which acts on the support at one end and on the link of the four-bar linkage opposite the support at the other end, and which spring has the function of, on the one hand, supporting the operation of the pneumatic cylinder during the swinging-up process and, on the other hand, securing the creel in the upper operating position. The lowering of the creel into the lower filling position is effected only manually, specifically both against the force of the positioning spring described below and against the force of a compressed air cushion located in a cylinder chamber which can receive compressed air, which is eliminated by the vent during the lowering process.

Disclosure of Invention

The aim of the invention is to improve the creel such that the manual handling is reduced or simplified even when the creel is swung down.

To accomplish this task, the present invention provides a creel device, including: a bobbin creel; a four-bar linkage mechanism comprising a fixed link and a movable link adapted to be mounted on a frame of a textile machine, wherein said creel is connected to said four-bar linkage mechanism in such a manner that said creel can be rotated relative to said frame from a lower loading position into an upper operating position; at least one pneumatic cylinder connected at a first end to said fixed link and at a second end to a first movable link of said movable link members, wherein said pneumatic cylinder is a double acting pneumatic cylinder capable of receiving compressed air at its first and second ends in order to rotate said creel from said operating position to said loading position; a gas spring having two ends and connected to the two ends of the four-bar linkage, wherein the gas spring is tensioned when the creel is rotated into the loading position, the fixed link has a first rotational axis, the first movable link has a second rotational axis, the first and second ends of the gas cylinder and the two ends of the gas spring are connected to the first rotational axis and the second rotational axis, respectively, and the gas spring is arranged substantially parallel to the gas cylinder.

In the known creel, the pneumatic cylinder acts with one end on a four-bar linkage section directly articulated to the fixed link of the support, i.e. the four-bar linkage, to be precise on a plate mounted on the rotatable link, while other aspects of the invention provide that the pneumatic cylinder is articulated with one end on the four-bar linkage section opposite the fixed support, in such a way as to reduce the footprint of the overall system.

According to the invention, a gas spring is provided which is articulated at both ends to a four-bar linkage and which is tensioned when the creel is pivoted into the loading position, whereby the energy stored in the gas spring is released when the creel is pivoted to support the operation of the gas cylinder on the one hand and the manual operation on the other hand.

According to the invention, depending on the weight of the creel with one or more feed bobbins, one pneumatic cylinder may be provided or two pneumatic cylinders may be provided in parallel. In the case where two pneumatic cylinders are provided, the gas spring is preferably provided at the midpoint of the two pneumatic cylinders.

In particular, when the creel according to the invention has a plurality of parallel receiving devices for receiving the yarn feed bobbins, it is advantageous if the creel is provided with two pneumatic cylinders, so that the creel is arranged substantially centrally between two operating positions to which the yarn drawn out of the yarn feed bobbins is fed.

The invention also provides a control valve for a pneumatic cylinder for operating a creel device according to the invention, having two pressure chambers which are separated by a piston mounted on a piston rod, said control valve comprising two 3/2 directional control valves which can be connected to a compressed air source and serve as switching valves, and a valve system which is connected between said switching valves and the pneumatic cylinder and by means of which, when one of the two switching valves is operated, one of the pressure chambers receives compressed air and the other pressure chamber is relieved via an exhaust throttle, characterized in that the valve system comprises two 3/2 directional control valves which are directly upstream of the pneumatic cylinder, and two non-return valves which are each located individually in a manifold which connects one of the switching valves to one of the two 3/2 directional control valves, and to which a control line which leads to the other of the two 3/2 directional control valves is connected Via the control line, the two 3/2 directional control valves can be adjusted between their compressed air flow position and their pressure relief position in such a way that

a) When the diverter valve is not operating, the 3/2 diverter valve is in its compressed air flow position, and the diverter valve is in a position to vent the manifold,

b) when actuated, one of the two switching valves is always in the compressed air flow position for the manifold to which it is connected.

The invention also provides a pilot valve having two compressed air connection channels and two changeover valves which can be actuated from the outside, wherein the two compressed air channels are connected to a pneumatic cylinder having two pressure chambers, acting in both directions and assigned to the creel device according to the invention, the two switching valves are used for alternately connecting one of the two compressed air connecting channels to a compressed air source and simultaneously discharging the other compressed air connecting channel in a controlled manner through a discharge throttle valve, a valve unit is arranged before each compressed air connecting channel, the valve units each comprise two valve bodies equipped with sealing rings, which are mounted coaxially to one another in a valve chamber in the shape of a stepped bore, and a return spring for urging the two valve bodies to maintain the closed position is installed between the valve bodies.

Drawings

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 shows a schematic side view of a textile machine, such as a flyer multi-strand twisting machine, having working positions at both ends in the machine direction, on the top side of which creels serving the opposite machine side are rotatably mounted.

Fig. 2 shows two opposing creels in a lower loading position according to a first embodiment of the invention.

Fig. 3 shows a different embodiment from fig. 2.

Fig. 4a shows a schematic diagram for an actuating valve for actuating a pneumatic cylinder in the rest position.

Fig. 4b shows the principle diagram in one of the two operating positions.

Figure 5 shows a side view of the pilot valve connected to a double acting pneumatic cylinder.

Fig. 6 shows a sectional view of the manipulated rice.

Fig. 7 shows a cross-sectional view along arrows I V-IV of fig. 6.

Fig. 8 shows one of the two valve units of the pilot valve according to the invention in an enlarged manner.

Fig. 9a shows a part of the valve housing in an enlarged sectional view.

Figure 9b shows two of the valve bodies outside the valve housing.

Detailed Description

The textile machine 1 schematically shown in fig. 1 is, for example, a flyer type multistrand twisting machine equipped with twisting spindles on both sides in the machine direction. Fig. 1 shows a creel 2 assigned to the left machine side and in its upper working position. The creel 2 assigned to the right machine side is shown in its lower loading position or filling position. According to fig. 2, each creel 2 is in the form of a double creel and is filled with four feed bobbins Sp, so that one creel can manage two adjacent twisting spindles each. The feed bobbin Sp may be a so-called single-strand feed bobbin for the outer yarn of the twisting process.

According to fig. 1, each creel 2 is fastened on the top side of a flyer multistrand twisting machine by means of a support 4 to a beam 3 extending in the longitudinal direction of the machine. On this support 4, which forms the fixed link of a four-bar linkage, two further links 5, 6 are articulated opposite one another, and on the ends of these two links, opposite the support 4, a fourth link 7 of the four-bar linkage is articulated.

For reasons of stability, the support 4 forming the fixed link is formed by two frame parts 4.1 which are arranged opposite one another at a distance and between which an upper shaft 4.2 and a lower shaft 4.3 are supported. The four-bar linkage 7 is formed in the form of a box with two opposite side walls 7.1 which are connected by an end wall 7.4 and between which an upper shaft 7.2 and a lower shaft 7.3, shown in dashed lines, are supported.

The connecting rod 5 is rotatably mounted on the two upper shafts 4.2, 7.2. The connecting rod 6 supported on the lower shaft 4.3 or 7.3 is box-shaped in cross section for stability.

In the embodiment of fig. 2, two parallel pneumatic cylinders 8 and a gas spring 9 between the two pneumatic cylinders 8 are mounted rotatably on the shafts 4.3 and 7.2 (fig. 3). As the name implies, the gas spring 9 consists of a cylinder into which a piston rod 9.1 and possibly a piston mounted thereon can be moved in order to precompress the gas volume located in the closed cylinder chamber.

According to fig. 3, only one pneumatic cylinder 8, apart from the pneumatic spring 9, is rotatably mounted on the shafts 4.3 and 7.2.

Each pneumatic cylinder 8 is designed in the form of a so-called pneumatic cylinder which can receive compressed air at both ends and comprises two compressed air chambers which are separated by a piston and which can alternately receive compressed air.

As shown in fig. 2, a holder 11 is fastened to the end wall 7.4 forming a fastening plate, which holder is provided at both ends with two receiving means 12 for the thread bobbin Sp.

An actuating valve is arranged in front of the central transverse plate 11 and is connected via a compressed air line, not shown, to a compressed air source on the one hand and to the two pressure chambers of the pneumatic cylinder 8 on the other hand.

In order to swing the creel down to the lower position shown in fig. 1 for filling the creel 2 with new feed bobbins Sp, the compressed air cylinder 8 receives compressed air, so that the piston rod 8.1 (see fig. 1) and the piston fixed thereto enter the cylinder chamber. Here, the gas spring 9 is simultaneously prestressed by the piston rod 9.1 being moved in.

After the filling or feeding process has ended, the piston rod 8.1 is moved away from the pneumatic cylinder again by corresponding valve actuation, so that the creel 2 is pivoted into its upper position, supported by the gas spring 9.

Fig. 5 shows a double-acting pneumatic cylinder 8 into which, at opposite ends, compressed air connections L6, R6 connected to a pilot valve 23 open. A piston (not shown) mounted on the piston rod 8.1 can receive compressed air via a compressed air connection L6 or R6, while the opposite cylinder or pressure chamber discharges air via another connection R6 or L6. A piston rod 8.1 is attached to the pneumatic cylinder 8, so that the pneumatic cylinder is articulated to two machine parts that can be moved relative to one another.

Fig. 4a shows the pilot valve 23 in the rest position. Fig. 4b shows an operating position in which the piston rod 8.1 can be moved in the direction of the arrow f1 into the pneumatic cylinder 8.

According to fig. 4a, two switching valves L1, R1, for example in the form of manual three-way two-position (3/2) switching valves, are connected to a compressed air source P by connecting lines L2, R2. The switching valves L1, R1 are connected to manifolds L3, R3, in which non-return valves L4, R4 are installed and lead to two 3/2 directional control valves L5, R5, which are connected or can be connected to the pressure chambers 8.3, 8.4 of the pneumatic cylinder 8 via lines L6, R6. Between the switching valve L1 and the non-return valve L4, a control line L7 branches off from the manifold L3 and leads to the 3/2 changeover valve R5 in order to switch 3/2 changeover valve R5 into the exhaust position against the force of the spring R8 when the control line L7 receives compressed air. The control line 7 has the same purpose of regulating 3/2 the directional valve L5 against the force of a return spring R8. The switching valves L1, R1 and the non-return valves L4, R4 and L5, R5 are preferably central valves which have a valve body equipped with sealing rings, which valve body can be moved against the spring force in a valve chamber with corresponding valve seats for the sealing rings.

When the switching valve L1 is operated by means of the operating element or push button L9 in the direction of arrow f2, a connection is made between the line L2 and the manifold L3, whereby the non-return valve L4 is opened and compressed air flows into the pressure chamber 8.3. At the same time, via a control line L7, which branches off from the manifold L3, the 3/2 selector valve R5 is set in the direction of the arrow f3 to the exhaust position, in which the pressure chamber 8.4 is exhausted via a line R6 and an exhaust throttle valve R10.

When the push button L9 is released, the switching valve L1 is pressed back into the rest venting position shown in fig. 4a by the return spring L11, as a result of which the control line L7 vents and thus the 3/2 changeover valve R5 returns to its original position again under the action of the return spring R5.

The pilot valve according to the invention thus, in a rough overview, combines four separate 3/2 directional valves and two non-return valves, which are preferably in the form of central valves and are logically connected to one another in such a way that, for example, when one of the two switching valves L1, R1 is manually operated, compressed air flows into one of the two pressure chambers of the pneumatic cylinder, while the other pressure chamber is vented as required via a vent throttle, so that when the previously operated switching valve is deactivated, the pneumatic cylinder can be kept both ends filled with compressed air and thus self-closing of the pneumatic cylinder or piston is achieved.

By actuating the switching valve R1 by means of the push button R9, the pressure chamber 8.4 receives compressed air, while the pressure chamber 8.3 is vented via a throttle valve L10 belonging to the 3/2 selector valve L5.

The actuating valve 23 shown in the preferred embodiment in fig. 6, 7, 8, 9a and 9b is distinguished by the fact that the valve elements or control elements described in connection with fig. 4a and 4b can be installed in a compact valve block in a space-saving manner.

According to fig. 6, the valve block comprises a lower part 25 and an upper part 26. A channel 27, which passes through the upper part 26 and can be connected to a compressed air source P, opens into a distribution chamber 28. In the lower part 25, two valve bodies 31, 31 'are supported or extend, which can be moved into the distribution chamber 28 by means of push buttons L9, R9 and against the force of return springs 33, 33'.

The valve body 31 is supported by means of a valve rod 31.1 in a bore 25.1 of the lower part 25 of the valve block with the formation of an annular gap, so that the section of the bore 25.1 located above the valve rod 31.1 is open to the outside, as is shown in fig. 6 for a push button L9, see the guide rod 31.1 'and the bore 25.1'.

A bore section 25.4 and a valve chamber 25.2 are connected to the bore 25.1, in which valve chamber a sealing ring 31.2 supported at both ends of the valve body 31 is guided in a sealing manner when the button R9 is actuated. The diameter of the bore portion 25.4 is greater than the diameter of the valve chamber 25.2, so that the sealing ring is arranged in the bore portion 25.4 when the switching valve is not operated in such a way that communication is established between the seal ring 31.2 and the environment via the opening 35. The valve chamber 25.2 opens into the valve chamber 28 with the formation of a valve seat 25.3. Above the sealing ring 31.2, a passage 35 is flanked into the valve chamber 25.2.

A sealing ring 31.4 of the valve body 31 is pressed in the rest position by a spring 33 against the valve seat 25.3, as is shown for the valve body 31' in fig. 6.

According to fig. 7 and 9a, a stepped bore is connected to the channel 35, in which a double valve unit is accommodated, which is formed by a first, lower valve body 36 and a second, upper valve body 38. The stepped bore has a guide section 39 which is connected to the passage 35 and with which a valve chamber 41 communicates, forming a valve seat 40. A valve chamber 43 is connected to the valve chamber 41 via a further valve seat 42, a valve chamber 45 is connected to the valve chamber 43 via a valve seat 44, and a vent passage 46 opens into the valve chamber 45.

The valve body 36 has a valve shank 36.1 which extends in a guide bore 39 and has a plurality of axial slots 36.2 distributed over its outer circumference. On the top side of the valve rod 36.1, there is a sealing ring 36.3 which in the rest position is pressed against a valve seat 40 by a restoring spring 36.4 which is mounted between the upper and lower valve bodies 38, 36.

The valve body 38 has a valve rod 38.1 guided in a valve chamber 41, which is substantially hollow-cylindrical with a side wall bore 38.2 and whose interior can communicate with the valve chamber 41. The valve body 38 carries a first, lower sealing ring 38.3 for cooperation with the valve seat 42 and a second, upper sealing ring 38.4 for cooperation with the valve seat 44. The valve body 38 is also provided with a piston 38.5 which moves sealingly in a valve chamber 45.

In addition to the valve units described in connection with the valve bodies 31, 36, 38, the pilot valve also comprises a second valve unit, which is constructed symmetrically to the above-described valve units, the specific parts of which are shown on the left side of fig. 6 and have the same reference numerals as the valve units on the right side of fig. 6, wherein the reference numerals of the valve units shown on the left side are given the upper right prime.

The two valve units are logically connected to each other by control lines L7, R7 according to fig. 4a, 4b and via a control channel 47 or 47 'connected to channel 35, 35'. Thus, according to fig. 6 and 7, the control channel 47 branching off from the channel 35 has a connecting channel 47.1 which traverses the upper part 26 of the valve block and opens with its outlet 47.2 into the valve chamber 45 'above the valve body 38'.

The valve unit shown on the right side of fig. 6 is operated by pressing the button R9. In this way, the sealing ring 31.4 of the valve body 31 is lifted off the valve seat 25.3 facing the valve chamber 28, so that compressed air flows into the passage 35 and the guide bore 39. In this way, the lower valve body 36 moves upward against the force of the return spring 36.4, the sealing ring 36.3 lifts off the valve seat 40, so that the compressed air flows through the radial slots into the valve chamber 41 and thus also into the valve chamber 43 through the wall opening 38.2 of the valve rod 38.1. The valve chamber 43 communicates via a side opening 43.1 with a connecting channel 50, to which a compressed air line R6 leading to the pressure chamber 8.4 is connected, so that compressed air can flow into the pressure chamber 8.4.

In order to be able to move the piston of the pneumatic cylinder unit 8, the air in the other pressure chamber 8.3 must be displaced. This is done in such a way that, via the control channel 47, the connecting channel 47.1 connected thereto and the through opening 47.2, compressed air flows into the valve chamber 45 'above the valve body 38', so that the valve body is pressed downward, whereby the sealing ring 38.4 'is moved away from its valve seat 44'. In this way, a connection is produced between the pressure chamber 8.3 and the part of the valve chamber 45 ' below the sealing piston 38.5 ' via the connecting lines L6 and 50 ', so that the pressure chamber 8.3 is vented via the vent channel 46 ' which is connected to the valve chamber 45 '.

In order to prevent a sudden pressure drop in the pressure chamber 8.3, the throttle valve L10 according to fig. 4a, 4b provides the exhaust passage 46' with an exhaust throttle valve (not shown). The same applies to the exhaust passage 46.

After releasing the button L9, the lower valve body 36 is pressed downwards by the return spring 36.4, so that the sealing ring 36.3 is pressed against the valve seat 40.

Since the compressed air supply via the venting channel system 47, 47.1 into the valve chamber 45 'upstream of the valve body 38' is omitted after the release of the button R9, the valve body 38 'is again pushed upward by the restoring spring 36.4', so that the sealing ring 38.4 'is pressed against the valve seat 44'.

Thus, an automatic self-closing of the pneumatic cylinder 8 as described above in connection with fig. 4a, 4b is achieved.

In order to be able to move the valve body 36 and therefore the sealing ring 36.3 of the valve unit shown on the right, on the one hand, toward the valve seat 30 and, on the other hand, to move the valve body 38 ' of the valve unit shown on the left, and therefore the sealing ring 38.4 ' bears against the valve seat 44 ', the cushion of compressed air in the channel system 35, 47, 47.1 has to be eliminated. For this purpose, the exhaust system between the duct 35 and the environment described above in connection with the button L9 in the rest position is used.

Claims (18)

1. A creel device, comprising:

a bobbin creel (2);

a four-bar linkage (4, 5, 6, 7) comprising a fixed bar (4) and a movable bar (5, 6, 7) adapted to be mounted on a frame of a textile machine, wherein said creel (2) is connected to said four-bar linkage in such a way that said creel can be rotated relative to said frame from a lower loading position into an upper working position;

-at least one pneumatic cylinder (8) connected at a first end to said fixed link (4) and at a second end to a first movable link of said movable link members (5, 6, 7), wherein for the purpose of moving said creel (2) from said operating position to said loading position, said pneumatic cylinder (8) is a double acting pneumatic cylinder capable of receiving compressed air at a first end and a second end thereof;

a gas spring (9) having two ends and connected to the two ends of the four-bar linkage (4, 5, 6, 7), wherein the gas spring (9) is tensioned when the creel (2) is rotated into the loading position, the fixed link (4) has a first rotational axis (4.3), the first movable link (7) has a second rotational axis (7.2), the first and second ends of the gas cylinder (8) and the two ends of the gas spring (9) are connected to the first rotational axis (4.3) and the second rotational axis (7.2), respectively, and the gas spring (9) is arranged substantially parallel to the gas cylinder (8).

2. Creel device according to claim 1, characterized in that said gas spring (9) is arranged between two of said pneumatic cylinders (8).

3. Creel device according to claim 1, characterised in that on the first movable link (7) of the four-bar linkage opposite to said fixed link (4) there are mounted receiving means (12) for receiving a yarn feeding bobbin (Sp).

4. A creel device according to claim 3, characterised in that a bracket (11) is fixed to the first movable link (7) of the four-bar linkage, and that the receiving means (12) for receiving the yarn feed bobbin (Sp) are mounted at each end of the bracket.

5. Creel device according to claim 1, characterized in that each pneumatic cylinder (8) is fixed at its second end to a first movable link (7) of the four-bar linkage, said first movable link being located opposite the fixed link (4).

6. A creel device according to claim 5, characterised in that the fixed link (4) forms a mounting and has two mutually spaced frame portions (4.1) between which two shafts (4.2, 4.3) forming links of a four-bar linkage are supported.

7. Creel device according to claim 1, characterized in that at least one four-bar linkage link (6) is designed box-shaped.

8. Creel device according to claim 1, characterised in that the first movable link (7) of the four-bar linkage has two spaced-apart opposite wall sections (7.1) which are connected to each other by an end wall (7.3) serving as a support for the cradle (11).

9. Operating valve for a pneumatic cylinder (8) for operating a creel device according to one of the claims 1 to 8, with two pressure chambers (8.3; 8.4) separated by a piston mounted on a piston rod (8.1), said operating valve comprising two 3/2 selector valves which can be connected to a compressed air source (P) and serve as selector valves (L1; R1) and a valve system connected between the selector valves and the pneumatic cylinder (8), by means of which valve system, when one of the two selector valves is operated, one of the pressure chambers is supplied with compressed air and the other pressure chamber is relieved via an exhaust throttle, characterized in that the valve system has two 3/2 selector valves (L5; R5) and two non-return valves (L4; R4) directly upstream of the pneumatic cylinder (8), the non-return valves are each located individually in a manifold (L3; R3) which connects one of the switching valves (L1 or R1) to one of the two 3/2 directional control valves (L5 or R5), to which a control line (L7 or R7) which leads to the other of the two 3/2 directional control valves (R5 or L5) is connected, by means of which the two 3/2 directional control valves (L5; R5) can be adjusted between their compressed air flow positions and their pressure relief positions, i.e. the compressed air flow positions are adjusted in such a way that the pressure relief positions are adjusted in each case

a) When the switching valve (L1; r1), the 3/2 diverter valve (L5; r5) is in its compressed air flow position, and the changeover valve is in a position such that the manifold (L3; r3) is discharged from the exhaust pipe,

b) when actuated, one of the two switching valves is always in the compressed air flow position for the manifold to which it is connected.

10. The pilot valve as claimed in claim 9, characterized in that the changeover valves (L1, R1) and the non-return valves (L1, R1) and 3/2 reversing valves (L5, R5) are central valves which have valve bodies equipped with sealing rings which can be moved against the spring force in valve chambers having respective valve seats for the sealing rings.

11. Control valve with two compressed air connection channels (50; 50 ') which are connected to a double-acting pneumatic cylinder (8) associated with a creel device according to one of claims 1 to 8 and with two pressure chambers, and with two changeover valves which can be actuated from the outside for alternately connecting one of the two compressed air connection channels to a compressed air source (P) and at the same time for the controlled venting of the other compressed air connection channel via a venting throttle, a valve unit is connected upstream of each compressed air connection channel (50; 50') and comprises two valve bodies (36, 36 '; 38, 38') which are provided with sealing rings and are mounted coaxially to one another in a stepped-bore-shaped valve chamber (41, 43, 45 or 41 ', 43', 45 ') and between them a pair of two valve bodies (36, 36'; 38, 38') to maintain the closed position of the return spring (33; 33').

12. The pilot valve according to claim 11, characterized in that all valves are designed in the form of central valves and are installed in a common valve group and are logically connected to one another in such a way that when one of the two switching valves is operated, one of the two pressure chambers of the pneumatic cylinder receives compressed air and the other pressure chamber is vented, preferably via a vent throttle, so that when the previously operated switching valve is deactivated, the pneumatic cylinder remains both receiving compressed air and thus self-closing of the pneumatic cylinder or its piston is achieved.

13. The control valve as claimed in claim 11 or 12, characterized in that the valve block (25, 26) has a distribution chamber (28) which is common to both switching valves and can be connected to a compressed air source in such a way that, when one of the two switching valves is actuated, a connection to the compressed air connection (50; 50') associated with the switching valve is produced.

14. The control valve as claimed in claim 13, characterized in that each switching valve has a valve chamber (25.2) which opens into the distribution chamber (28) with a valve seat (25.3) formed and is intended for receiving a valve body (31) which can be displaced into the distribution chamber (28) counter to the force of a restoring spring (33) and which has, at its end which can be displaced into the distribution chamber (28), a sealing ring (31.4) for cooperating with the valve seat (25.3), a passage (35) side which opens into the associated compressed air connection passage (50) opening into the valve chamber (25.2).

15. The control valve as claimed in claim 14, characterized in that at the end which does not open into the distribution chamber (28) a bore section (25.4) is connected to the distribution chamber (25.2), the diameter of which bore section is greater than the diameter of the valve chamber (25.2), the valve body (31) being provided at its end facing the bore section (25.4) with a sealing ring (31.2) which, when the valve body (31) is pressed into the distribution chamber (28), moves sealingly in the valve chamber (25.2), and which, when the switching valve is not operated, is mounted in the bore section (25.4) in such a way that a communication is established between the passage (35) and the environment past the sealing ring (31.2).

16. The control valve as claimed in claim 15, characterized in that in the valve block (25, 26) a stepped bore is provided for receiving a double valve unit consisting of a first valve body (36) and a second valve body (38), which stepped bore has a guide section (39) which is connected to the passage (35), to which a first valve chamber (41) is connected with the formation of a valve seat (40), to which a second valve chamber (43) is connected via a valve seat (42), which second valve chamber has a larger diameter than the valve chamber (41) and a lateral opening which opens into the compressed air connection (50) and is connected via a valve seat (44) to a third valve chamber (45), into which opens an exhaust passage (46) which opens to the outside, the first valve body (36) having a valve rod (36.1) guided in the guide bore (39), said valve rod having at least one axial slot on its outer circumference and being fitted on its top side with a sealing ring (36.3) cooperating with an expansion seat (40), the second valve body (38) having a valve rod (38.1) guided for displacement in a valve chamber (41) which is of hollow cylindrical shape with a side wall bore (38.2) for establishing a communication between the valve chamber (41) and the valve chamber (43) in the open position of the first valve body (36), the second valve body (38) being provided with a first sealing ring (38.3) for cooperating with the valve seat (42) and a second sealing ring (38.4) for cooperating with the valve seat (44), the valve body (38) being provided with a piston (38.5) which is sealingly displaceable in the valve chamber (45) in such a way that, when the second valve body (38) receives compressed air, it bears against the first and second valve bodies (36), 38) the return spring (36.4) is moved so that the sealing ring (38.4) is lifted off the valve seat (44) and thus a communication can be produced between the outlet channel (46) and the second valve chamber (43) and thus the compressed air connection channel (50).

17. The control valve as claimed in claim 16, characterized in that an exhaust throttle valve is assigned to the exhaust duct (46).

18. The control valve as claimed in claim 16, characterized in that a channel system (47, 47.1) is connected to the channel (35), and the double valve unit connected upstream of the second compressed air connection channel (50 ') opens into the cylinder chamber (45') in such a way that the second valve body (38 ') of the second double valve unit is displaced against the force of a restoring spring (36.4') assigned to the second double valve unit, so that a communication can be produced between the second compressed air connection channel (50 ') and the outlet channel (46') of the second double valve unit.