Fluid-activated adjustment and manoeuvre devices of this type are known previously and are, for example, described in DE 706 193, US 3 863 546 or US 3 905 275.

These known fluid-activated adjustment and manoeuvre devices generally include a space arranged in a housing that is divided into two chambers via a displaceable moveable piston device accommodated in the space, screw-like running grooves that are rotatable relative to a centre axle extending through the space and arranged to establish communication for a fluid medium between the said chambers, and an inlet and an outlet respectively arranged at the adjustment and manoeuvre device.

There are normally at least two screw-like grooves arranged in the known adjustment and manoeuvre devices named above, whereby in order to achieve an axial movement of the piston device, one groove introduces a fluid into one of the chambers at the same time as an equivalent amount of fluid is discharged from the second chamber via the second groove.

There is, however, a wish to achieve a simplified adjustment and manoeuvre device in which the said axial displacement of the piston device can be achieved with merely one single screw-like groove that is rotatable relative to a centre axle.

The aim of the present invention is thus to achieve a fluid-activated adjustment and manoeuvre device of the type stated above.

This aim is achieved by the fluid-activated adjustment and manoeuvre device according to the invention having the characteristics specified in the claims.

In an embodiment of the invention described below, the fluid-activated adjustment and manoeuvre device forms part of a valve for a pressurised medium that includes a valve cone or piston that is axially displaceable and moveable within its valve housing from a closed position to a fully open position to control in a continuously adjustable manner the amount of fluid per unit of time that is allowed to flow through the valve. The valve for a pressurised medium is designed as single sleeve capable of being screwed into a valve block and that through the invention has the advantage of being a single compact unit that not only includes the flow-regulating cone but also the controlling pilot valve that controls the position of the cone in the housing by regulating a pilot flow originating from the pressurised medium flow.

The invention is described in more detail below with reference to the enclosed drawing where Fig. 1 shows schematically a longitudinal cross-sectional view of a valve for a pressurised medium in which a fluid-activated adjustment and manoeuvre device according to the invention is included, Fig. 2 shows the valve according to Fig. 1 in a closed position, and Fig. 3 shows the valve in an open position.

The fluid-activated adjustment and manoeuvre device according to this invention described here in the form of a valve for a pressurised medium includes a housing 1 with an inlet 2 and an outlet 3 in the form of openings that lead in respectively out from a existing inner space 4 in the housing for an axially displaceable but non-rotatable moveable piston or cone 5 arranged in this space. A similar non-rotatable but axially displaceable piston in an inner space can, from a pure design point of view, be achieved in a number of different ways and suitably through the outside of the piston and the inside of the housing being given equivalent non-rotational symmetrical cross-sectional profiles or through the interaction between a notch and groove.

Figs. 1 and 2 show piston 5 in a position that seals the exit B of the valve, and Fig. 3 shows the said piston in a position where the valve is open in which the entry A and exit B of the valve are connected with one another by a flow path that allows a flow of pressurised medium to pass through the valve in the direction indicated by the arrow 6.

When the valve is closed, as is evident from Figs. 1 and 2, the lower edge section of piston 5 abuts tightly with the seat 7 of the valve that surrounds the outlet 3. The outside of the housing 1 is designed with a thread 8 to interact with an equivalent thread in an application hole 101 in a valve block 100 to connect the valve to the intended flow channel 102. In other words, the housing 1 functions as a sleeve that quickly and simply can be screwed in firmly in an connection hole 101 intended for it in valve block 100 and in which connection hole there are also arranged sealings on both sides of the inlet 2 as well as above the threaded section of the valve housing for sealing the housing against the wall of the connection hole.

Each sealing is arranged in its own peripheral groove in the outside of the valve housing and each includes a sealing gasket 9 and a support ring 10.

At one of its ends, the valve for a pressurised medium is sealed off by means of an end wall 11 that is connected with the valve housing 1 via a threaded joint 12 in order to, together with the end surface 13 of the piston of the said valve housing, demarcate an inner space that forms a pilot flow chamber 14, which will be described thoroughly below.

The piston 5 has a second end surface 15 that closes the exit B of the valve by interacting with the surface of the seat 7 that surrounds the outlet 3. As is shown in Figs. 1 and 2, the

piston 5 is held in its closed position by means of a holding force P that acts on the end surface 15 of the piston 5 that faces the pilot flow chamber 14.

From the end of the piston 5 that faces the pilot flow chamber 14, an axle 16 emerges that passes through the end wall 11 and that in a known manner is tightly sealed against the said end wall 11 with regard to the fluid that the valve is intended to control.

Here it should be realised that the term fluid as it is used in this description naturally applies to gaseous and liquid forms of the medium. As such, axle 16 can rotate relative to the end wall 11 but cannot be axially displaced relative to the end wall 11, and is accommodated in the piston 5 via a first axial drill hole 17 that is located in the centre of the piston. As is evident from observing Figs. 2 and 3, the section of the axle 16 that is accommodated in the piston 5 is given a screw-like groove 18 that runs along the periphery and that can be rotated relative to a centre axis X that extends through the piston 5.

With regard to the fluid used, the outside of the piston 5 is sealed in a known manner against the inside of the limiting wall of the inner space 4 arranged in the housing 1.

When the piston 5 is located in a position where the exit B of the valve is closed, as is shown in Fig. 2, a ring-shaped chamber 19 is demarcated between the lower tapered section 20 of the piston 5 and the section of the valve housing 1 that forms the outlet of the valve. As is evident from Figs. 2 and 3, the piston 5 has a second axial drill hole 21 whose one end opens in the ring-shaped chamber 19 and whose other end is situated inside the piston 5, whereby the said axial drill bole 21 extends from the ring-shaped chamber 19 in a direction towards the end of the piston device 5 from which the first axle 16 emerges. A third axial drill hole 22 has one end that opens in the end of the piston 5 that has a reduced diameter, i. e. the section designated with the reference number 20. The other end of the third axial drill hole 22 is located inside the piston 5 and extends from its opening end in a direction towards the end of the piston 5 from which the first axle 16 emerges. The second and the third drill holes, 21 and 22 respectively, end at approximately the same axial level in the piston 5.

As is evident from Figs. 2 and 3, the piston 5 is also provided with a radial drill hole 23 running all the way through it and that is connected to all of the said axial drill holes 17,21 and 22, whereby the said radial drill hole 23 extends through the first axial drill hole 17 in which axle 16 is accommodated. In the areas of its ends, the radial drill hole 23 is sealed against the fluid that is used by means of sealings 24. A spring 25 is fitted between the end of the piston device from which the axle 16 emerges and a recess in the end wall 11.

The said spring 25 surrounds the axle 16.

The valve for a pressurised medium shown in Figs. 1-3 works in the following way: A pressurised fluid is supplied to the entry A and inlet 2 of the valve as symbolised by the arrow 6A. The said fluid then enters the ring-shaped chamber 19 and thereafter the pilot flow chamber 14 via the second axial drill hole 21, the radial drill hole 23 and the groove 18 on the axle 16. In this context, it should be noted that axle 16 has rotated, as symbolised in Fig. 2 by the loop 26 with an arrow, to a position where the groove 18 establishes a connection for the fluid medium between the radial drill hole 23 and the pilot flow chamber 14. In this way, the same pressure will prevail in the ring-shaped chamber 19, that is at the entry A to the valve and in the pilot flow chamber 14. The pressure prevailing in the pilot flow chamber 14 gives rise to the holding force P that acts on the end surface 13 of the piston 5 and, because of the prevailing conditions related to the areas involved, is greater than the opposing force that depends on the pressure in the entry A, and that therefore holds the piston 5 in its closed position as long as the said connection between the entry A to the valve, inlet 2 and the pilot flow chamber 14 is maintained.

To ensure that the connection between the radial drill hole 23 and the pilot flow chamber 14 is maintained during the whole of the displacement of the piston 5 in a downwards direction as viewed in the figure, the width of the groove 18 must be adapted to the length of the axial displacement of the piston 5. Alternatively, the axial movement of the piston 5 can be followed by an equivalent appropriate turning of the axle 16 during the axial displacement of the piston 5.

The axial displacement of the piston 5 upwards is illustrated in Fig. 3, whereby fluid is supplied via entry A and inlet 2, as symbolised by the arrow 6A. The axle 16 has at this time rotated, as illustrated by loop 27 with the arrow, to a position where there is no connection between the lower ring-shaped chamber 19 and the upper pilot flow chamber 14, which is why the pressurised medium will thus only act in the lower ring-shaped chamber 19. As the axle 16 has rotated to a position seen in Fig. 3 where groove 18 has established a communication between the pilot flow chamber 14 and the radial drill hole 23, fluid can be discharged from the pilot flow chamber 14 via the groove 18, the radial drill hole 23, the second axial drill hole 22 and outlet 3. This makes it possible for the piston 5 to be displaced upwards in space 4 in the manner shown in Fig. 3 where this movement is limited by the width of the groove, but which can also be executed as a continuous linear movement if an equivalent rotation of the axle 16 takes place at the same time so that the groove 18 and the channels 21-23 communicate with one another. When the piston 5 lifts off from the seat 7

arranged at the outlet 3, a passage for the fluid will be formed between the sealing end surface 15 of the piston 5 and the seat 7, as illustrated by the arrow 28. Fluid can thereafter flow out of the housing 1 through the fluid outlet 3 and the exit B, which is illustrated with the arrow 6B. The spring 25 acts as a dampening means during the movement of the piston 5 upwards and downwards. The spring 25 is, however, not absolutely essential for the function of the valve.

When the function of the flow valve has been described with reference to Figs.

1-3, a rotation of the axle 16 by a specified angle has caused a specific equivalent linear displacement of the piston 5. A step-like displacement of the piston 5 has thus taken place.

Within the scope of the invention, one can nevertheless consider that a continuous, controlled rotation of the axle 16 and therefore also of the piston 5 takes place, which means that the groove 18 and the channels 21-23 communicate with one another in a specific combination during the whole of the linear displacement of the piston 5, i. e. a continuous displacement of the piston 5 will take place. The said continuous, controlled rotation of the axle 16 can be executed by means of a motor, for example.

The present invention is not limited to that described above and shown in the drawings but can be changed and modified in a number of ways within the scope of the invention as stated in the following claims.