DE2319030A1 - MEDIUM FLOW AND PRESSURE REGULATING VALVE FOR HYDRAULIC MOTORS - Google Patents

Description

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506 R * frafch to Kflln
Frenitenforster Strasse 137

Gardner-Denver Company Quincy, Illinois, (¥ .St.A.)

^Ir medium flow and pressure control valve for hydraulic motors "

The invention relates to a medium flow and pressure control valve for hydraulic motors. '. ■ ■

With many devices operated by pressure medium, it is desirable to control or regulate the position and the direction of movement as well as the force or pressure applied to the Device or exercised by the device itself.

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For example, when drilling rock with drills mounted on mounts for reversible movement therealong, it is desirable to be able to move the drill at different speeds along the mount. It is also desirable to be able to move the drill accurately to a certain position on the mount and to control the drill so that a certain feed force is exerted on the drill rod and the drill bit, the latter controlling function somewhat depends on the rock conditions. Hydraulically controlled feed devices for rock drilling machines, as known from US Pat. No. 3,189,1o3, and also various other applications for hydraulic motors with corresponding control functions, require control circuits which include directional control valves, flow regulators and pressure regulators. In known hydraulic control systems, it is normally necessary to provide separate devices to provide for the various control functions that must be provided, and this has resulted in expensive and complicated hydraulic circuits with numerous lines and components. Particularly in the case of rock drilling machines, in which the operating conditions place high demands on the device, it is desirable to provide hydraulic systems that have the smallest number of components and, accordingly, the smallest number of lines and connections .

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The invention provides a pressure medium flow and pressure regulating control before, which ensures a regulation of the pressure medium, which is a pressure medium motor or a corresponding pressure medium device is supplied to a pressure value that corresponds to the pressure of a pilot medium that is being used, to put the control into function. The invention also provides a pressure regulating controller that is used for directional control of pressure medium at controlled pressure for reversible actuation of a pressure medium motor or the like. cares.

The pressure regulating controller according to the invention consists of one Control valve for supplying medium directly to a reversible pressure medium motor or the like. under a regulated pressure, which essentially corresponds to a pilot medium pressure that is used to operate the control valve.

With the control valves according to the invention is a pressure medium flow and pressure regulation control provided, which is a so-called Forms multi-directional control valve, which is combined with a pressure medium regulator in a single valve, wherein while the valve can also be used as a flow control valve which is able to cover a considerable area to regulate medium flows for the operation of reversible pressure medium motors and the like.

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The flow and pressure regulation control according to the invention comprises also a differential pressure control valve which is actuatable to pilot actuators to pressure medium under different pressures or the like. feed, for example, opposite pilot actuator chambers of the reversible flow control and pressure control valve according to the invention.

The invention also provides a flow and pressure regulation control for pressure medium-operated feed mechanisms of rock drilling machines, with a simplified control circuit for a Reversible movement of a drilling machine along a support with a target speed and a target feed force for Drilling and provides for retraction of the drill bit with the drill steel from a borehole at a set speed. At a Pressure medium control circuit in combination with a pressure medium actuated Feed mechanism for a rock drilling machine according to the invention is simple and reliable Control circuit that controls the feed force and the position controls the drill with high accuracy.

The invention is explained in more detail below with reference to the drawings explained. In the drawings are:

Fig. 1 is a longitudinal section through a medium flow and Pressure control valve according to the invention,

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Fig. 2 is a section through a differential pressure control valve according to the invention,

3 is a schematic view of a control system for the feed mechanism of a rock drilling machine according to the invention and

FIG. 4 is a section on line 4-4 of FIG. 3.

In Fig. 1, a flow and pressure control valve 1o is shown. The valve 1o comprises a housing 12 with a bore 14 in which a cylindrical sleeve 16 is seated in a tight fit. the Sleeve 16 is provided with a cylindrical bore 18 and with spaced circumferential grooves 2o, 22, 24, 26 and 28 provided, each comprising radially extending channels 3o, which open into the bore. As shown in FIG. 1, the grooves 2o, 22, 24, 26 and 28 are each connected with openings 32, 34, 36, 38 and 4o in the housing 12. The sleeve is held in place by opposing flange caps 42 and 45, which are fastened to the housing in a suitable manner and have chambers which are formed by recesses 44 and 45 are. These chambers point in the direction of the bore 18 of the sleeve. The caps 42 and 43 are also bored 46 and 48 which lead from the recesses 44 and 45 to suitable threaded openings 5o and 52, respectively.

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The valve 1o comprises distant / ¹ a cylindrical closing member 54 which is movably mounted in a tight fit in the bore 18. The closing member 54 is provided with peripheral recesses 56 and 58 under a portion 6o lying between the recesses. The lot 6o is dimensioned so. that an interruption of the flow of medium from the feed opening 36 to one of the recesses 56 or 58 is provided when the closing member is in the position shown in FIG. The recesses 56 and 58 also have such a dimension that the closing member 54 interrupts the openings 32 and 34 in their communication with the recesses 56 and 58, respectively, when the valve is in the position shown in FIG. The closing member 54 can, however, be moved in order to connect the opening 32 with the opening 34 via the recess 56, as can the opening 36 with the opening 38 via the recess 58. The closing member 54 can also be moved in the opposite direction to the The opening 34 is to be connected to the opening 36 via the recess 56 and at the same time the opening 38 is to be connected to the opening 4o via the recess 58.

The closing member 54 is also provided with longitudinal chambers 62 and 64, each of the opposite end faces 66 and 68 open. A channel 7o connects the chamber 62 with the recess 58, and a channel 72 connects the chamber 64 with the recess' 56. The chambers 62 and 64 each comprise a cylindrical free piston 74 which is slidably seated in them. The free piston

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74 each has an end face 76 and a flange part 78 which lies against the relevant end face of the closing member 54. Channels 8o in the free piston open into the relevant Chambers 62 and 64 and can be brought into communication with recesses 44 and 45 in caps 42 and 43, if they be relocated accordingly in the chambers. Second free pistons 82 are slidably seated in the bores 46 and 48 of the caps 42 and 43 and lie against the free piston 74. The free pistons 82 each include channels 84 which lead to the openings 5o and 52, respectively to open. The channels 84 are also with the recesses 44 and 45 in the caps 42 and 43 in the position shown in FIG in connection. Each of the free pistons 74 may be formed integrally with the associated free piston 82, but they will made in separate pieces to wedge the free piston as a result of misalignment of the bores 46 and 48 with respect to the chambers 62 and 64 to be avoided.

The closing element 54 is tensioned into the central position shown in FIG. 1 by opposing helical springs 86 and 88, which are seated in the recesses of the cap 42 and 43. The springs 86 and 88 each rest against a flange sleeve 9o. The sleeves 9o in turn bear against the end surfaces 66 and 68 of the closure member 54 and are provided to ensure that the ^{closure member is centered by the springs 1} 86, 88 when unbalanced compressive forces are applied to the end surfaces of the closure member.

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The chambers formed by the recesses 44 and 45 form together with the surfaces 66 and 68 on the closing member 54 Means for moving the closing member 54 to the pressure medium supply opening 36 with the first opening 34 or the second To bring opening 38 in connection. For example, if pilot pressure medium through the opening 5o and the channel 84 in the free piston 82 is introduced into the recess 44, it acts on the End surface 66 to move the closure member 54 so that the opening 34 communicates with the opening 36 via the recess 56 assuming, of course, that the compressive force exerted on end surface 66 is sufficient to overcome the clamping force, which is exerted by the counteracting spring 88. Such movement of the closure member 54 causes the free piston 7.4, which sits in the chamber 64, moves with the closing member, and the free piston 82, which sits in the bore 48, becomes moved to a position in which the channel 84 through the wall of the Bore 48 is blocked to allow communication with the opening 52 with the recess 45 to prevent. When the closure member is in a position as described above has been, the opening 38 is connected to the opening 4o via the recess 58. The closing member 54 can be in the opposite Are moved in the direction from the central position in order to connect the opening 36 with the opening 38 via the recess 58, and at the same time the opening 32 is connected to the opening 34 via the recess 56. By means of pressure the opening 52 and through the channel 54 is passed to the end

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_ ~ _g _ 2313030

to apply surface 68, the closing member 54 against the Tensioning force of the spring 86, which is seated in the recess 44, can be moved. A little more than a slight movement of the locking link to connect the opening 36 with the opening 38 prevents a connection of the recess 44 with the opening 5o in the Cap 42 by removing the free piston 82 seated in bore 46 causes the channel 84 to be blocked by the wall of the bore 46. Although the free pistons 82 sit in a tight fit in the bores 46 and 48, the channels 84 in certain positions To substantially block the closing element, leakage of pressure medium from the recesses 44 or 45 can occur between the bores 46 and 48 and the free piston 82 to allow movement of the closure member 54 when the Channels 84 are blocked. The movement of the closure member to expose the opening 36 can be for one as well as for the other Direction of movement can be precisely controlled by regulating the medium pressure that acts on the end surfaces 66 and 68 to to overcome the tension force of the respective opposing springs 88 and 86, possibly also opposing pressure forces, which can act on the surface 83 of a free piston 82. The valve 1o can therefore be precisely controlled remotely to measure quantities to deliver dosed to pressure medium either to the opening 34 or to the opening 38, in which the closing member 54 in the corresponding Location is brought.

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- ίο - 23190

The valve 1o ensures a directional control of the Druckini ttelflusses as well as for a regulation of the flow rate by precisely controlling the reversible movement of the closing member 54 to expose the opening 36. The valve 1 ο can also be turned on can be set to regulate the pressure of the medium flowing to either port 34 or port 38 from port 36. When pressure medium is supplied to the opening 5o, for example, to cause the closure member to migrate so that the opening 34 is connected to the opening 36, flows through the channel 72 medium from recess 56 to chamber 64 to the end face 76 of the free piston 74 to act. A compressive force as a result of the meditation that acts on the free piston 74 is displaced the free pistons 74 and 82 in such a way that the channel So is brought into communication with the recess 45 and the chamber 64. Of the Recess 45 from the recess 56 supplied pressure medium acts on the end surface 68 of the closing member, and thereby the closing member is opposed towards the middle position the compressive force with which the end surface 66 moves through Pilot pressure medium is applied, which is fed to the recess 44 will. The pressure of the medium in the recess 45 is essentially the same as the pressure in recess 56, when the recess 45 is not in communication with the opening 52 via channel 84 in free piston 82 as a result of the movement the same is located. It is assumed that under all operating conditions the end surfaces 66 and 68 'have the same cross-sectional areas, which are exerted by the pressure medium in the relevant

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openings 44 and 45 are applied. Accordingly, the closing member 54 migrates so that the flow of pressure medium from of orifice 36 is controlled to regulate the pressure of the medium flowing to orifice 34 by substantially the pressure of the pilot control medium to correspond, which is fed to the recess 44 through the opening 5o. The springs 86 and 88 can with be provided a spring characteristic that has no significant effect on the pressure control operation of the valve 1o for the Pressure range that is normally used in hydraulic systems is being worked on.

The valve 1o can be operated in the same way to to regulate the pressure of the medium that is fed to the opening 38. When pilot pressure medium is supplied to port 52, and not the opening 5o, the closing member 54 of the valve is moved so that the opening 36 with the opening 38 in communication is brought, and medium in the recess 58 flows through the Channel 7o and moves the free piston 74 in the chamber 62 to bring the channel 8o into communication with the recess 44. Corresponding applied pressure medium from the recess 58, the end surface 66 to move the closure member 54 so that the Flow of medium from opening 36 to opening 38 is regulated until the pressure in the recess 58 and in the opening 38 corresponds essentially to the pressure of the pilot control medium, which is fed to the recess 52. >

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™ I £ _ ™

The valve 1o thus works as a pressure regulating valve as well like as a directional flow control and flow regulating valve. When the valve 1o is operated, the flow to either To regulate opening 34 or to opening 38, there is a flow control alone without a pressure control, as long as the channels in the free piston 74 against a connection with the recesses 44 or 45 are blocked. By regulating the medium pressure for opening §2 in order to create a pressure force that acts against the surface S3 which the free piston 74 in the position shown in FIG. 1 with respect to the closing member 54 holds, pressure medium is prevented by the recess 56 from entering the recess 45. When regulating the flow of medium to the opening 38 prevents pressure medium that so is regulated that it acts on the surface 83 on the free piston 82, which sits in the recess 44, corresponding to a displacement of the associated free piston 74 to the pressure medium to bring with the chamber or recess 44 of the recess 58 and the opening 38 in communication, as long as the pressurization of the area is less than the compressive force with which the area 83 is acted upon. The free pistons 74 form that is, means that respond to a target medium pressure either in the first opening 34 or in the second opening 38, which act on the surfaces 76 in order to move the free pistons so that that the recesses 56 or 58 are brought into connection with the relevant recesses 44 or 45 in order to

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act that the closing member 54 performs the pressure control function.

As can be seen from the foregoing, the valve 10 can be controlled to provide a specific direction of the medium flow, a specific flow rate, and pressure regulation by regulating the pressure of the medium that is fed to the openings 5o and 52. Suitable means for supplying medium pressure under increased pressures either to the opening t> 0 or 52 with a simultaneous reduction in the pressure at the relevant opposite opening are shown in FIG. In Fig. 2, a pilot pressure medium control valve 92 is shown. The valve 92 comprises a housing 94 having a cylindrical bore 96 which is closed at one end by a cap, polyhedron, is suitably attached to the housing 94. A cylindrical valve closing member 1oo with radially inwardly inclined surfaces 1o2 and 1o4, which form a chamber 1o6 in the bore 96, is seated inside the bore 96. The closing member 1oo comprises a thread portion 1o8 which is seated in a cap 11 o which is fastened in a suitable manner to the housing 94 and has a thread portion 112 with a corresponding mating thread. The valve closing member 100 further comprises an end portion 115 to which an operating handle 114 is removably attached. Upon rotation of the valve member 100 by the handle 114, the closing member migrates in the longitudinal direction in the bore 96 by means ″ which are formed by the cooperating threaded sections 1o8 and 112. The valve 92 further comprises channels 116

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and 118 in housing 94, which intersect bore 96. The channels 116 and 118 are in a pressure medium connection with a pressure medium supply channel 112 via capillary channels 112 and 124, respectively. The channels 112 and 124 can have the same cross section and have an equal length in order for an equal resistance to provide for the medium flow through them, or alternatively they can be provided in various dimensions to allow greater flow through one channel than the other. The channels 116 and 118 can by suitable. Lines 178 and 13o each with .den openings 5ο and 52 of the Control valve loo in Fig. 1 connected. The valve 92 comprises further- a medium outflow or backflow channel 126, which the Hole 96 intersects. An auxiliary drainage channel 128 carries leakage medium back to channel 126 from an end portion 13o of bore 96. That Valve 92 can be actuated to increase the medium pressure in channel 116 increase and at the same time reduce the medium pressure in the channel 118 by turning the handle 114 in order to move the closing element 1oo in the longitudinal direction in the bore 96 away from the cap 98. Such movement diminishes the cross-sectional area of a diaphragm between the inclined Surface 1o2 and the opening of the channel 116 in the bore 96 is formed is. At the same time, the cross-sectional area of a diaphragm between the inclined surface 1o4 and the increases Opening of the channel 118 in the bore 96 is formed in order for a comparatively unthrottled. Flow from medium channel 118 through chamber I06 to channel 126.

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With an essentially constant pressure supply of medium to the channel 12o, the above-described movement is thus effected of the closing member 1oo an increase in the medium pressure in the channel 116 and an associated decrease in media pressure in channel 118. Rotation of handle 114 to produce longitudinal movement of the closing member 1oo in the opposite direction to that described above leads to an increase in the pressure of the medium in the channel 118 and a decrease in the pressure of the medium in the channel 116. In the position of the closing element shown in FIG. 2, the same pressure prevails in the channel 116 and 118, and both channels pass small amounts of medium through the Chamber 1o6 to drain channel 126. The valve 92 can therefore advantageously be used as a means in connection with the regulating valve Io to reduce the medium pressure in openings 5ο and 52 to regulate, so that the valve 1o for regulating the medium flow and the pressure is actuated to a reversible pressure medium motor or the like.

The aforementioned control valves 1o and 92 provide a special good regulation for the feed mechanisms for rock drilling machines, which work with reversible pressure medium motors to a rock drilling machine along a feed carriage to move forward and backward. In Fig. 3 and 4, the valves 1o and 92 are in a hydraulic control circuit for the feed mechanism 134 of a rock drilling machine. The feed mechanism 134 for rock drilling machines

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is characterized by a carriage 136 on which a rock drilling machine 1 ^- 38 is slidably mounted, which comprises a bearing plate 139. The drill 138 is intended to drive an extendable drill string 14o comprising drill rods 141 and 143 which are coupled together end to end in a known manner. The drilling machine 138 can be provided in a rotating or impact-rotating design, both of which are known in the field of rock drilling. The feed carriage 136 has elongated, spaced-apart parts 142, which are connected to one another in a suitable manner by support parts 144. The feed mechanism 134 comprises a reversible hydraulic feed motor in the form of a double acting hydraulic cylinder 146. The hydraulic cylinder 146 is fixedly attached to the feed carriage 136 by the bracket 148 and comprises an extendable piston rod 150 with a bracket 152 at the free end thereof. The bracket 152 rotatably supports a sprocket 154 which engages two flexible chains 15, 156, one of which is shown in FIG. These chains are suitably attached to the drill 138 at one end 157 and to the feed carriage 136 at the opposite end 158. A third feed chain 16o is fastened at one end 162 to the feed carriage 136 and is in engagement with the sprocket 154 and, conversely, is wrapped around sprockets 164 and 1b -_>, which are mounted on opposite ends of the carriage 136. The other end 168 of the chain 16o is connected to the drill 138.

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The feed mechanism 134 represents an embodiment which can be used in conjunction with the control circuit described below. Feed mechanisms with reversible Rotary motors in combination with cables, chains or spindles can also work in connection with the invention be used.

A control circuit for the feed mechanism 134 includes one Hydraulic pump 17o, which is suitably from a pressure medium motor 172 can be driven. The pump 17o is through lines 174 and 176 to the channel 12o of the valve 92 and connected to the opening 36 of the valve 1o to each pressure medium feed essentially under constant pressure. the Channels 116 and 113 of valve 92 are each with the openings 5o and 52 of the valve 1o are connected by lines 17S and 18o. The openings 34 and 38 of the valve 1o are opposite one another Ends of the hydraulic cylinder 156 are connected by respective lines 182 and 184. Channel 126 in valve 92 is connected to a low pressure tank 186 by line 188, and * ports 32 and 4o of valve 1o are with connected to the discharge medium of the tank 186 by the line 19o. The control circuit shown in Fig. 3 can be actuated to pressure medium an opening 192 of the hydraulic cylinder to extend the piston rod 15o and thus the drill to pull along the feed carriage 136 through the chains 156. Conversely, by pressurizing an opening 194 of the Cylinder is fed, the piston rod 15o is in the

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Cylinder retracted to oppose the drill 138 Direction to pull through the chain I6o. In rock drilling machines with drilling machines mounted on mounts, it is desirable, the drill exactly on the feed carriage to position in order to add or remove drill rods from the drill pipe I4o, for example in the shape of the rods 141 and 143 shown in FIG. Correspondingly, the control circuit in Fig. 3 by the actuation of the valve 92 to Supply of pressure medium to the opening 5ο of the valve 1o below a higher pressure than that is supplied to the opening 52, the valve 1o to meter pressure medium to the cylinder 146 so that the drill string I4o is retracted so that the drill is brought into a position.,. "to the Add another drill rod to the drill rod I4o. To move the drill 1.3ö into the intended position on the mount 136 to bring, the valve 92 is actuated to increase the pressure either at the opening 5ο or 52 only enough so that the Closing member 54 against the tension force of the counteracting spring and against the counteracting pressure force to - "move, with the surface 83 on the relevant free piston 82; is applied. A movement of the drill 138 along the mount 136 for positioning purposes usually requires no significant pressure in the cylinder 146, and the pressure of the PilQt control medium, with which the surfaces 83 "are acted upon, can be determined so that it is sufficient" to move the

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To prevent free piston 74 with respect to the closure member 54. Further, when the drill unexpectedly encounters an obstacle or the feed mechanism during positioning movement hooks, the pressure of the medium that is fed to the cylinder 146 rises, essentially only up to the pressure of the Openings 5o or 52 supplied medium, since the valve 1o begins to function as a pressure regulator.

However, when the drill 138 is actuated, the drill string to push forward with considerable force during an ear process, becomes the pressure of the medium supplied to the opening 52 of the valve 1o by the movement of the closing member 1oo increased in order to further narrow the aperture, which is caused by the Channel 118 and the inclined surface 1o4 is formed, and at the same time the pressure in the opening 5o is reduced to ensure that the valve member 74 is freely movable in order to connect the recess 58 with the recess 44. Accordingly, enough the medium pressure in the cylinder 146 and at the opening 38 of the valve 2o normally off, as a result of a resistance to the penetration of a rock formation by the drill string I4o to immediately move the free piston 74, thereby pressurizing the fluid the recess 44 can be fed in order to start operation of the valve 1o in the pressure control function, so that the desired feed force on the drill 138 is maintained.

309881/1042

Also, in rock drilling operations, it is often desirable to quickly reverse the direction of movement of the drill, and repeated to create a reciprocating pumping action with the drill string and with the drill bit to loosen Remove debris from the borehole. As can be seen from the above, the control circuit according to the invention can be actuated in order to quickly reverse the direction of movement of the drill 138 along the mount 136 by actuating the valve 92 is to alternately increase the medium pressure to one of the openings 5o or 52 of the valve 1o, while the pressure at the other opening is reduced in order to displace the closure member 54 so that the opening 36 either with the Opening 34 or with the opening 38 is connected. The compact one and relatively straightforward control circuit, consisting of valves 1o and 92, can be actuated to power drill 138 to control only for a positioning movement, or to control a variable feed force with an automatic regulation exert on the target feed pressure. Due to the ability of the valve 1o to pass a substantial range of flow rates Being able to regulate the valve is also for a quick movement and quick change of direction in the movement of the drill 138 taken care of.

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Claims (7)

- 21 claims 1.) Medium flow and pressure control valve, marked through a housing (12, 16) with a medium supply opening (36), a first opening (34) and a second opening (38) for directing medium into the valve and out of the valve and outlet openings (32, 4o) a closing member (54) in the housing (12, 16) which is movable so that the supply opening (36) alternates with the first Opening (34) or the second opening (38) is brought into communication, wherein a surface (66) on the closing member (54) lies in a chamber (44) and is responsive to pilot pressure medium which can be fed to the chamber (44) such that the closing member (54) is moved so that the supply opening (36) is brought into communication with the first opening (34) is, a surface (68) on the closing member (54) lies in a chamber (45) and responds to pilot pressure medium, the the chamber (45) for moving the closing member (54th) can be fed in such a way that the feed opening (36) with the second Port (38) is brought into communication, and responsive to a target pressure in the first or second port (34, 38) movable valve elements (74) for supplying pressure medium to the chambers (44, 45) for moving the Closing element (54) for regulating the pressure of the medium which is fed to the first or second opening (34 »38) will. 309881 / Ί 0.42 -22- 2. Control valve according to claim 1, characterized in that g e k e η nz e i c h η et that the closing member (54) is a cylindrical " The drical piston is used for the stroke movement in the valve housing (12,16) is arranged in such a way that the feed opening "(36) is brought into communication with the openings (34, 38). 3. Control valve according to claim 2, characterized in that that the valve elements (74) are arranged in chambers (62, 64) in the closing member (54) and that Closing member (54) has a channel (7o) for conducting pressure medium from the second opening (38) to the chamber (62) 'and a channel (72) for directing print medium from the first Includes opening (34) to chamber (45). 4. Control valve according to claim 3, characterized in that each of the valve elements (74) has a channel (8o), a first pressure surface (76) which is supported by the pressure medium from the first or second opening (34, 38) can be acted upon, and comprises a second pressure surface (83) which is opposite the first pressure surface, the pressure surfaces responding to the application of pressure by a pilot pressure medium in such a way that the valve elements (74) are moved so that a flow of pressure medium from the first and second openings (34, 38) to the opposite. lying chambers (44 _f 45) is prevented by the channels (8a) * Γ -23 .- 5. Control valve according to claim 4, "characterized through the combination with a pilot pressure medium control valve (92) and lines (178, 18o) for guiding pilot pressure medium to the chambers (44, 45) of the valve (1o) to act on the pressure surfaces (66, 68) on the closing member (54) and the second pressure surface (83) on the movable Valve elements (74), wherein the pilot pressure regulating valve (92) can be actuated in such a way, the pilot pressure medium is fed into one of the chambers (44, 45) in the valve with a pressure which is higher than that of the medium to the other Comb is such that the closing member (54) moves the pressure medium is supplied from the supply opening (36) to one of the first and second openings (34, 38). 6. Control valve according to claim 5, characterized in that that one of the valve elements (74) for Prevention of the flow of pilot pressure medium into the other chamber of the valve (1o) upon movement of the closing element (54) and to prevent the flow of pressure medium from one opening (34, 38) to the other chamber is actuated, while a pressurization of the first surface (76) of the valve element (74) is less than one Pressurization of the second surface (83) of the valve element (74) is. 309881/1042 -24- 7. Control valve according to claim 6, characterized by the combination with a feed mechanism (I34) for a rock drilling machine with a carriage (136), a drill motor (138) which is mounted for reversible movement on the mount (136) along, and one Pressure medium motor (146) -for moving the drill motor (138) along the mount (136), a pressure medium source (17o), a line (176) for connecting the pressure medium source (17o) to the feed opening (36) and lines (182, 184), which connect the openings (34, 38) of the control valve (1o) with the pressure medium motor (146) in such a way that the . Control valve (1o) for regulating the medium flow to the pressure medium motor (146) for moving the drill motor (138) reversible along the mount (136) and to regulate the pressure of the pressure medium motor (146) supplied Medium can be actuated to a value which corresponds essentially to the pressure of the pilot pressure medium that the valve (1o) is fed through the pilot pressure medium control valve (92). 3,098 8 1/1042 &' ι. Blank page