GB1593884A - Hydraulically actuated control valve - Google Patents

Description

(54) HYDRAULICALLY ACTUATED CONTROL VALVE (71) We, ROTATOR NORWAY A.S., a Norwegian Company, of P.O. Box 25, 4645 Nodeland, Norway, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particu larly described in and by the following statement:- This invention relates to hydraulically actuated control valves for controlling the flow of hydraulic fluid to a hydraulic device.

Such valves are used as control units in systems with pressurised oil as the working medium.

According to the invention there is pro vided a hydraulically actuated control valve for controlling the flow of hydraulic fluid to a hydraulic device, the valve including: a slide valve comprising a valve member slidably mounted in a valve body having a first port for connection to a hydaulic fluid- supply, second and third ports for connecti-on to a hydraulic device and a fourth port for returning the hydraulic - -fluid, the valve member having a first position- in which the second and third ports are closed and a second position in which the first port is in fluid communication with. the second port and the third port is in fluid communication-with the fourth port, resilient means biassing the valve member to its first position, a first.pilot valve, and first piston and cylinder means in fluid communication -with an -outlet .ofthe. first pilot valve and- drivingly connected .to the slide valve member, the arrangement being such that, in use,. in a first state pf the first pilot valve hydraulic fluid flows. through the first pilot valve into the first piston abd cylinder means moving the slide valve member against the bias of the resilient means into its second position and in a second state of the.. first pilot valve hydraulic fluid in the first piston and cylinder means. is vented and the resilient means returns. the slide valve - member to its first position, wherein the slide valve is provided with an auxiliary valve in the first port arranged such that when in use, -,th,e -slide valve member moves from its first position to its second position the auxiliary valve remains closed until the slide valve member has almost reached its second position and the hydraulic connections aetween the valve member and the valve body have been completed.

According to another aspect of the invention there is provided a hydraulic device and a hydraulically actuated control valve as defined above, the control valve being hydraulically connected to the hydraulic device and controlling the flow of hydraulic fluid to the hydraulic device.

By way of example, a hydraulic control valve. embodying the invention will now be described with reference to the accompanying drawings, in which Figure 1 shows an axial vertical section through the valve and Figure 2 shows an axial horizontal section through the valve.

Referring to the drawings the hydraulic valve.comprises a slide valve body or housing 1 having two end parts 2 in each of which a respective pilot valve is fitted.

The valve housing 1 has. an. elongate chamber 13 in which an elongate slide valve member 3 of generally square- cross-section is arranged for sliding movement in the cham ber. Each end of the chamber 13 is of en larged cross-section and houses an annular plate 30.biassed.by a compression spring 4 located .between the plate and the end part 2 towards the centre of the chamber 13. The plate 30 is sized such that it cannot enter the central section of.the chamber 13. In the natural position of the slide valve member 3 it is centrally located in the chamber 13 with the plates 30 abutting the ends of the valve.

member and located at the inner ends of the enlarged parts of the chamber.

Each end of.the valve member 3 is provided.

with a cylindrical piston 5 which passes through the plate 30 and is received in a cylinder 6 defined in.the end part 2 by machining of the end part 2. The cylinders 6 communicate via passageways with ports 31 of the pilot valves.

Each pilot valve has an zoutlet chamber 32 connected to an oil" return-.-path path a manner described below, a ball 22 located over. a valve seat 33, which upon downward movement of a spindle 21 is pressed down onto the valve seat 33, a ball 24 located below a valve seat 34, a spindle 23 between the balls 22 and 24, and an inlet chamber 35 connected, in use, to a pressurised supply of oil in a manner described below. Above the spindle 21 and acting as a top cover for the pilot valve is a solenoid unit 17 having a magnetised spindle 20 which also extends out of the top of the unit as a button 18. The solenoid unit 17 is bolted onto the end part 2 and closes over the top of the pilot valve.A terminal box 19, to which the electric power supply for the solenoid unit 17 is connected, is attached to the unit 17.

In the unactuated state of the pilot valve the spindle 20 is in a raised position and the pressure of oil in the inlet chamber 35 holds the ball 24 against its valve seat 34, thus lifting the spindle 23 and, in turn, lifting the ball 22 off the valve seat 33 so that the port 31 is in fluid communication with the outlet chamber 32 but not with the inlet chamber 35. Upon actuation of the pilot valve the spindle 20 is depressed, pressing the spindle 21 down onto the ball 22 so that the ball is pressed onto the valve seat 33; depression of the ball 22 in turn depresses the spindle 23 and the ball 24 so that the ball 24 is pushed away from the valve seat 34 against the force of the inlet oil supply.

Thus in the actuated position of the pilot valve the part 31 is in fluid communication with the inlet chamber 35 but not with the outlet chamber 32.

The elongate slide valve member 3 has four transverse parallel equispaced passages 50, 51, 52, 53, a longitudinal passage 37 eonnecting the inner two transverse passages 51, 52 and another two passages 14, 36 transverse to the member 3, intersecting the transverse passages 50, 53 respectively and running at right angles thereto.

The slide valve body 1 has seven passageways which terminate in the chamber 13.

Six of these passageways are located in the central section of the chamber and comprise three equispaced passageways (38, 39, 40) terminating at the upper side of the valve member 3 and three equispaced passageways (41, 42, 43) terminating at the lower side of the valve member 3.. Each of these passageways is fitted with a sealing sleeve 8 which is biassed against the valve member 3 by a spring disc 9; in the case of the upper passageways the spring discs 9 bear against the ends of the passageways and in the case of the lower passageways the spring discs 9 bear against sleeves 44 fixed in the outer ends of the passageways. The sleeves 8, 44 are provided with suitable sealing rings to prevent oil leaking around the outside of the sleeves.

The. passageways 38, 40 and 42 are blind passageways, the passageway 39 is connected to a passage 10 which in use, is connected in a manner described below to a supply of pressurised oil. The passageways 41 and 43 are, in use, connected to respective hydraulic lines of the hydraulic device to be controlled by the valve. The seventh passageway 15 in the valve body 1 extends through the valve body 1 from the chamber 13 and, in use, defines the oil return flow path.

As shown in the horizontal section through the control valve, an auxiliary valve 25 is provided. This valve has a waisted valve member 45 located in the passage 10 and having a follower part 46 biassed by a spring into contact with a cam surface 47 formed on the slide valve member 3. In the position shown in the drawing the valve 25 is in its closed position so that the passage 10 is obscured from view by the valve member 45.

It will be clear that upon substantial movement of the slide valve member away from its central position the inclined part of the cam surface 47 presses the valve member 45 outwards against the bias of the spring thus opening the passage 10.

In operation of the control valve, a pressurised oil supply is connected to the passage 10. The passage 10 terminates in an inlet (not shown) at the exterior of the valve body.

The inlet chamber 35 of each pilot valve is connected to the passage 10 upstream of the auxiliary valve 25, by a passage 48 (shown in dotted outline in Figure 2). Similarly the outlet passageway 15 is connected to the outlet chamber 32 of each pilot valve by a passage 49 (shown in dotted outline in Figure 2).

In operation the passageway 15 carries the oil after its passage through a hydraulic device; thus the outlet from passageway 15 is normally connected to a reservoir of oil which may serve as the source for oil to be pressurised and passed to the passage 10.

It will be appreciated that in the position shown in the drawing with both pilot valves in an unactuated state, the pilot valve oil inlet chambers are disconnected from the cylinders 6 by the balls 24, the auxiliary valve 25 is closed and the passageways 38 to 43 are closed. Thus in this position the valve in use acts as a hydraulic lock, i.e.

it prevents flow to and from the hydraulic device.

If the pilot valve on the right hand side (as seen in the drawings) is now actuated, either by depression of the bottom 18 or actuation of the solenoid 17, then pressurised oil flows from the inlet of the passage 10 into the inlet chamber 35 through the port 31 into the right hand cylinder 6 (as seen in the drawings). This flow of pressurised oil moves the slide member 3 to the left (as seen in the drawings) against the bias of the left hand spring 4 and the oil in the left hand cylinder 6 (as seen ill the drawings) is displaced from the cylinder through the port 31, past the ball 22, into the outlet chamber 32 and out of the valve through the passageway 15.

As the slide valve member 3 approaches the end of its travel the cam surface 47 reacts on the follower 46 to press the valve member 45 of the auxiliary valve 25 outwards thus opening the passage 10. Immediately after the opening of the passage 10, the slide valve member 3 arrives at the end of its travel. In this position the passages 51, 52 and 53 are aligned with the passageways 38, 41, the passageways 39, 42 and the passageways 40, 43 respectively.

With the slide valve member 3 in this position pressurised oil flows through the passage 10, passageway 39, passage 52, passage 37, passage 51, passageway 41 and to the hydraulic device. Oil returning from the device flows through passageway 43, passage 53 and passage 36 into the slide valve chamber 13 and exits from the control valve through the return passage 15.

If now the left hand pilot valve is actuated and the right hand pilot valve deactuated oil will flow into the left hand cylinder 6 from the inlet chamber 35 and out of the right hand cylinder 6 into the outlet chamber 32 and the slide valve member 3 will be moved from the left to the right ("left" and "right" being as shown in the drawings). During most of the travel of the valve member 3 the auxiliary valve 23 is closed but towards the end of the travel of the member 3 the valve 25 is again opened. In the end position of slide valve member 3 the passages 50, 51 and 52 are aligned with the passageways 38,41 the passageways 39, 42 and the passageways 40-, 43 respectively.

With the slide valve member 3 in this position pressurised oil flows through the passage liO, passageway 39, passage 51, passage 37, passage 52, passageway 43 and to the hydraulic device. Oil returning from the device flows through passageway 41, passage 50 and passage 14 into the slide valve chamber 13 and exits from the control valve through the return passageway 1-5.

Thus it will be seen that actuation of one pilot valve causes oil to flow through, a hydraulic device in a first direction and actU- ation of the other pilot valve causes oil to flow through there hydraulic device in the reverse direction. Upon deactuation of both pilot valves the springs 4 act to return the slide valve member 3 to its central position in which the- valve acts as a hydraulic lock for the hydraulic device.

It will now- be clear that the auxiliary valve. 25 prevents oil flowing from passage 10 until the slide member 3 is almost in its final end position and the connections between the passages in the member 3 and passageways in the valve body 1 have been totally established. This is important since without the valve 25, when the passageway 39 overlaps only a part of a passage in the slide valve member 3, oil would be able to flow directly out of the passageway 39 into the chamber 13 and out through the return passageway 15.As a result of such a flow the pressure of the oil at the inlet to passage 10 would drop and, since in this embodiment the pilot valves have the same oil source, the pressure of the oil in the cylinder 6 would correspondingly drop to the inlet where further movement of the slide valve member 3 would not occur so that the slide valve would remain in a partly open position.

The control valve described above combines the controlling character of a magnetically operated pilot valve and the locking properties of a hydraulic lock. Furthermore the valve is of a safe design such that it is suitable for use in gas-filled areas and other such areas where there is a danger of an explosion.

WHAT WE CLAIM IS: 1. A hydraulically actuated control valve for controlling the flow of hydraulic fluid to a hydraulic device, the valve including: a slide valve comprising a valve member slidably mounted in a valve body having a first port for connection to a hydraulic fluid supply, second and third ports for connection to a hydraulic device and a fourth port for returning the hydraulic fluid, the valve member having a first position in which the second and third ports are closed and a second position in which the first port is in fluid communication with the second port and the third port is in fluid communication with the fourth port, resilient means biassing the valve member to its first p'osition, a first pilot valve, and first piston and cylinder means in fluid communication with an outlet of the first pilot valve and drivingly connected to the slide valve member, the arrangement being such, that, in use, in a first state of the first pilot valve hydraulic fluid flows through the first pilot valve into 'the first piston and cylinder means moving the slide valve member against the bias of the resilient means into its second position and in a second state of the first pilot valve hydraulic fluid in the first piston and cylinder means is vented and the resilient means returns the slide valve member to its first position, wherein the slide valve is- prov ded with an auxiliary valve in the first port arranged such that when, in use, the slide valve member moves from its first position to its second' position the auxiliary valve remains closed until the slide valve member has almost reached its second position and the hydraulic

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (12)

**WARNING** start of CLMS field may overlap end of DESC **. 31, past the ball 22, into the outlet chamber 32 and out of the valve through the passageway 15. As the slide valve member 3 approaches the end of its travel the cam surface 47 reacts on the follower 46 to press the valve member 45 of the auxiliary valve 25 outwards thus opening the passage 10. Immediately after the opening of the passage 10, the slide valve member 3 arrives at the end of its travel. In this position the passages 51, 52 and 53 are aligned with the passageways 38, 41, the passageways 39, 42 and the passageways 40, 43 respectively. With the slide valve member 3 in this position pressurised oil flows through the passage 10, passageway 39, passage 52, passage 37, passage 51, passageway 41 and to the hydraulic device. Oil returning from the device flows through passageway 43, passage 53 and passage 36 into the slide valve chamber 13 and exits from the control valve through the return passage 15. If now the left hand pilot valve is actuated and the right hand pilot valve deactuated oil will flow into the left hand cylinder 6 from the inlet chamber 35 and out of the right hand cylinder 6 into the outlet chamber 32 and the slide valve member 3 will be moved from the left to the right ("left" and "right" being as shown in the drawings). During most of the travel of the valve member 3 the auxiliary valve 23 is closed but towards the end of the travel of the member 3 the valve 25 is again opened. In the end position of slide valve member 3 the passages 50, 51 and 52 are aligned with the passageways 38,41 the passageways 39, 42 and the passageways 40-, 43 respectively. With the slide valve member 3 in this position pressurised oil flows through the passage liO, passageway 39, passage 51, passage 37, passage 52, passageway 43 and to the hydraulic device. Oil returning from the device flows through passageway 41, passage 50 and passage 14 into the slide valve chamber 13 and exits from the control valve through the return passageway 1-5. Thus it will be seen that actuation of one pilot valve causes oil to flow through, a hydraulic device in a first direction and actU- ation of the other pilot valve causes oil to flow through there hydraulic device in the reverse direction. Upon deactuation of both pilot valves the springs 4 act to return the slide valve member 3 to its central position in which the- valve acts as a hydraulic lock for the hydraulic device. It will now- be clear that the auxiliary valve. 25 prevents oil flowing from passage 10 until the slide member 3 is almost in its final end position and the connections between the passages in the member 3 and passageways in the valve body 1 have been totally established. This is important since without the valve 25, when the passageway 39 overlaps only a part of a passage in the slide valve member 3, oil would be able to flow directly out of the passageway 39 into the chamber 13 and out through the return passageway 15.As a result of such a flow the pressure of the oil at the inlet to passage 10 would drop and, since in this embodiment the pilot valves have the same oil source, the pressure of the oil in the cylinder 6 would correspondingly drop to the inlet where further movement of the slide valve member 3 would not occur so that the slide valve would remain in a partly open position. The control valve described above combines the controlling character of a magnetically operated pilot valve and the locking properties of a hydraulic lock. Furthermore the valve is of a safe design such that it is suitable for use in gas-filled areas and other such areas where there is a danger of an explosion. WHAT WE CLAIM IS:

1. A hydraulically actuated control valve for controlling the flow of hydraulic fluid to a hydraulic device, the valve including: a slide valve comprising a valve member slidably mounted in a valve body having a first port for connection to a hydraulic fluid supply, second and third ports for connection to a hydraulic device and a fourth port for returning the hydraulic fluid, the valve member having a first position in which the second and third ports are closed and a second position in which the first port is in fluid communication with the second port and the third port is in fluid communication with the fourth port, resilient means biassing the valve member to its first p'osition, a first pilot valve, and first piston and cylinder means in fluid communication with an outlet of the first pilot valve and drivingly connected to the slide valve member, the arrangement being such, that, in use, in a first state of the first pilot valve hydraulic fluid flows through the first pilot valve into 'the first piston and cylinder means moving the slide valve member against the bias of the resilient means into its second position and in a second state of the first pilot valve hydraulic fluid in the first piston and cylinder means is vented and the resilient means returns the slide valve member to its first position, wherein the slide valve is- prov ded with an auxiliary valve in the first port arranged such that when, in use, the slide valve member moves from its first position to its second' position the auxiliary valve remains closed until the slide valve member has almost reached its second position and the hydraulic

connections between the valve member and the valve body have been completed.

2. A control valve as claimed in claim 1 in which a second pilot valve and a second piston and cylinder means in fluid communication with an outlet of the second pilot valve and drivingly connected to the slide valve are provided, the arrangement being such that, in use, in a first state of the second pilot valve hydraulic fluid flows through the second pilot valve into the second piston and cylinder means moving the slide valve member against the resilient bias of the resilient means into a third position in which the first port is in fluid communication with the third port and the second port is in fluid communicatin with the fourth port, and in a second state of the second pilot valve hydraulic fluid in the second piston and cylinder means is vented and the resilient means returns the slide valve member to its first position, and such that when, in use, the slide valve member moves from its first position to its third position the auxiliary valve remains closed until the slide valve member has almost reached its third position and the hydraulic connections between the valve member and the valve body have been completed.

3. A control valve as claimed in claim 2 in which the first position of the slide valve member is a central position and the second and third positions of the slide valve member are symmetrically disposed on opposite sides of the first position.

4. A control valve as claimed in claim 2 dr' 3 in which the first piston and cylinder means is disposed at one end of the slide valve member and the second piston and cylinder means is disposed at the other end of the slide valve member.

5. A control valve as claimed in claim 4 in which the resilient means comprises first spring means at one end of the slide valve member biassing the member away from that end and second spring means at the other end of the slide valve member biassing the member away from that end.

6. A control valve as.claimed in any of claims 2 to 5 in which the slide valve member comprises an elongate member having first, second, third and fourth equispaced transverse passages extending from a first side of the member to a second side, a fifth longitudinal passage extending between the second and third passages, and sixth and seventh passages extending from the first and fourth passages respectively to the exterior of the slide valve member; in which the slide valve body has an elongate chamber in which the slide valve member is located, first,.second and third passageways terminating in the chaniber at the first side of the slide member in equispaced relationship, fourth, fifth and sixth passageways terminating in the chamber at the second side of the slide member opposite the first, second and third passageways respectively, the second, fourth and sixth passageways constituting said first, second and third ports respectively and the first, third and fifth passageways being blind, and a seventh passageway extending through the slide valve body from the elongate chamber and constituting said frouth port; and in which the arrangement is such that in the first position of the slide valve member, the second, fourth and sixth passageways are closed thereby, in the second position of the slide valve member the second and fifth passageways are aligned with the third passage, the first and fourth passageways are aligned with the second passage, the third and sixth passageways are aligned with the fourth passage and the seventh passage is in fluid communication with the valve chamber, and in the third position of the slide valve member, the second and fifth passageways are aligned with the second passage, the third and sixth passageways are aligned with the third passage, the first and foruth passageways are aligned with the first passage and the sixth passage is in fluid communication with the valve chamber.

7. A control valve as claimed in any preceding claim in which the or each pilot valve has an inlet for connection to a hydraulic fluid supply, a port providing fluid commuication between the piston and cylinder means and the pilot valve and an outlet for returning the hydraulic fluid, and in which in the first state of the pilot valve the inlet is in fluid communication via the port with the piston and cylinder means and the outlet is closed and in the second state of the pilot valve the inlet is closed and the outlet is in fluid communication via the port with the, piston and cylinder means.

8: A control valve as claimed in any preceding. claim in which the or each pilot valve can be controlled manually or electrically by a solenoid.

9. A control valve as claimed in any preceding claim in which the or each piston and cylinder means comprises a piston member on the slide valve member -and .:a cylinder defined by the pilot valve housing.

10. A control valve as claimed in any preceding claim in which the slide valve member is of square cross-section.

11. A hydraulically actuated control valve for controlling the flow of hydraulic fluid to a hydraulic device, the valve being substantially as herein described with reference. to and as illustrated by the accompanying drawings.

12. A hydraulic-devicé and a hydraulicälly: actuated control valve as claimed in any preceding claim, the control valve being hydraulically connected to the hydraulic device and controlling the flow of hydraulic fluid to the hydraulic device.