DE2305579A1 - REMOTE CONTROL SYSTEM ACTIVATED BY THE PRESSURE OF A FLOWABLE MEDIUM - Google Patents

Description

Our reference: G 1520

Actuated by a pressure of a flowable medium

Remote control system

The invention relates to a remote control system of the type actuated by the pressure of a flowable medium with a force balance in which a power output part adjusted by a controlled motor loaded in the opposite direction by a spring will. The controlled motor is controlled by an auxiliary control slide supplied with changing actuation pressure. The movement of the auxiliary control spool also controls the Effectiveness of a stop that limits the movement of the power output part. It is such an arrangement provided that the power output part is under the exclusive control of the auxiliary control slide and regardless of inadvertent changes in the magnitude of the actuation pressure applied to the controlled motor move over a normal range of motion or up to an expanded limit for motion can.

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In particular, the invention relates to an improvement in a Fems expensive system actuated by a pressure of a flowable medium, with a power output part set by a controlled pressure motor, with a spring acting in the opposite direction on the motor and with a control circuit which can be displaced from a neutral pitch auxiliary control valve to the supply of the controlled motor with a variable pressure, characterized by a co-operating with the Iieistungsabgabeteil and between an active and an inactive position the movable home: blow, in which it allows the controlled motor, the power output member via a normal or to move over a larger range of motion and by a device which actuates the stop and responds to the movement of the auxiliary control slide for setting the stop into the active position when the auxiliary control slide is in the normal range of motion b efinds, and in the inactive position when the auxiliary spool has been moved beyond the normal range of motion.

The type of force balancing having a through a pressure fluid medium operated remote control system is known. Generally this has a remote control system a controlled motor, which is controlled by a pressure-grading auxiliary control slide with a flowable Medium for one drive is supplied and one power delivery part or a controlled part against the counteracting force of a spring adjusts. The through the pressure exerted by the spring depends on the deflection of the spring and the output pressure of the auxiliary control spool depends on the position of its movable inlet or outlet Control element abc, therefore the system provides at least an approximate correspondence between the positions the control element and the power output part

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In some applications this remote control system has the power output part two critical positions and it is imperative that the power output part is not inadvertently moved over the first position into the second position - for example, this is the case, when the power output part is a spool of a directional control spool used in a hydraulic drive system and when the slide is both a position for powered downward movement and a drain position. In this area of application, the slide is usually equipped with an auxiliary pressure spring, which is arranged so that it is effective in the position for a driven downward movement and the further movement of the slide depends on the formation of a control pressure that is significantly higher than that of the pressure makes required to move the slider to the powered downward movement position. Since the formation of this higher pressure requires an additional movement of the control element of the auxiliary control spool, the presence of the auxiliary spring represents a certain security against the risk of an inattentive Operator unintentionally moves the main slide to a drain position rather than a position for one sets driven downward movement. Two versions of this particular embodiment of a remote control with force compensation are disclosed in U.S. Patents 3,110,135 and 3,604,313.

Although certain systems of the aforementioned type by the use of specially adapted components for a satisfactory operation can be produced, experience shows that the embodiment for a Mass production of relatively cheap systems, for example

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for such systems used in all-terrain ErdlDewegungsfallzeugen, is not suitable. To do this there there are various reasons. First, manufacturing tolerances have a significant impact on the ratio between the delivery pressure of the auxiliary control slide and the displacement of its control element. Second is the curve of the pressure over the displacement of the auxiliary control spool is not linear, but has a fast, increasing ^ slope when the control is above about the last third of its movement path up to the end of the stroke is moved. Ultimately, the manufacturing tolerances and the operating conditions affect the pressure disadvantageous that the controlled motor requires a certain position to move the slide. From the The combined effect of these factors results in the predetermined displacement of the control element of the auxiliary control slide that involves movement of the spool to a position for powered downward movement should result, in some cases is unsuitable to cause the spool to reach this position. In other cases, the spool can be made to move in d'ie drain position. This unintentional movement into the disposal lineup can be prevented by increasing the preload by the auxiliary spring. However, this measure is therefore unsuitable because they assign a larger part of the auxiliary control spool stroke for use makes a control pressure formation necessary, which is needed to overcome the force of the auxiliary spring in the times in which it is desirable to move the spool into the divider. From this it follows that the section of the hub that leads to the ver. slide the spool between the neutral

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position and the position is available for a powered downward movement, would have to be reduced. This means that it would be very difficult for the operator to perform the dimensioning operation of the adjustment control slide to monitor.

The invention is therefore based on the object of an improved remote control system with force compensation to create that from the standpoint of reducing the risk of inadvertent movement of the power output part is more reliable in a position beyond its normal range of motion and that under use can be made of interchangeable parts from one production. According to the invention is the power output part provided with a limit stop, which is movable between an active and an inactive position, in which it allows the part to one to wander through a normal or an enlarged range of motion. The limit stop is exclusively through the movement of the auxiliary control spool is controlled and it is only set to an inactive position when when the control element of the auxiliary control slide over a predetermined position in its range of motion is postponed. Since, in contrast to the auxiliary spring used previously, the limit stop is a fixed one Holding device is and since it is only in the active position it is a force that stops the movement supplies, the auxiliary control slide can have a predetermined Have position in which it generates a control pressure that is always sufficient to move the power output part to the limit of its normal range of motion regardless of the influences of the tolerances and the operating conditions. In the preferred

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Embodiment, the border to chi ag also acts as a seat for the compression spring or for one of the compression springs in the case of a multiple-spring arrangement of the power output part, and therefore the spring pressure is in the postponed position of the performance division the same or not much greater than the spring pressure, that in the normal limited position of the power compartment is exercised. This arrangement ensures that the controlled pressure y is the same as the controlled pressure Engine the power output part towards the normal limit can push, necessarily sufficient to the power output part to the postponed limit when the stop is in its inactive position is set. It follows that the entire gradation range of the auxiliary control slide is used can be a normal shift of the power output part to execute. This is an advantage in cases where the power output part is a spool of a direction control slide valve, as it provides the operator with a good monitoring of the drive ' effect of this slide.

For a better understanding of the invention is a in the Drawing illustrated embodiment described. The drawing shows the schematic in the single figure Representation of a typical hydraulic drive circuit with the remote control system of the invention.

According to the drawing, a remote control system 1 is used to control a spool 2 of a conventional Adjusting the direction control slide 3 for four positions » The direction control slide 3 is located in a hydraulic drive circuit, which has a supply

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pump 4-, a reservoir 5 and a double-acting Power cylinder 6 has. The spool 2 has the following main divisions:

a. a neutral position in which there is a flow to and from opposite working spaces 6a and 6b of one Cylinder 6 blocked and creates an open center for a relief path from the pump 4- to the Storage container 5 leads,

b. a lifting position which is to the right of the neutral position and in which the spool is the The relief path closes and the work spaces 6a and 6b connect with the pump 4 · and the storage container 5, respectively ,

c. a position for a powered downward movement which is to the left of the neutral position and in which the spool closes the relief path and the working spaces 6a and 6b connects with the storage container 5 and with the pump 4 and

d. an expiration position that is beyond the position for a driven downward movement and in which the slide piston drives the pump 4- to the reservoir 5 relieved and in which he the work spaces 6a and 6b via a feedback path connects a restricted flow leading to the reservoir 5.

In addition to these main positions, the slider-r piston 2 also has the usual ranges of dimensioning positions between the lifting position and the position for a driven downward movement and the neutral position are interposed, and in each of these Dimensioning positions, the spool 2 divides the flow between the expanding working space of the cylinder

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Linders 6 and the reservoir 5 in a ratio on, which depends on the distance by which the spool has been moved from its neutral position.

The slide piston 2 is pressed into the neutral position shown by a pair of centering springs 7 and 8. Each spring acts on the spool via one or the other collar of a collar set 9 and 11 or 12 and 13 · When the spool 2 is in its neutral pitch, the collar rings come out 9 and 11 engaged with their stationary seats, however have the collars 12 and 13 in the axial direction of their seats a distance X which corresponds to one half of the inactive area of the spool. on In this way, the spring 7 and the spring 8 are effective over the entire range of movement of the slide piston 2 is only effective after the spool has been moved far enough to be a supply path from the Pump 4 to open one of the working spaces 6a and 6b. This sequential capture of the springs is a desirable feature as it minimizes the risk of part of the stroke of the subsequent auxiliary control slide described to activate the Slide 3 is required.

The slide body 2 of the directional control slide 3 is moved from its neutral position by one of a pair of controlled pressure motors 14 and 15 acting in the opposite direction are displaced. Any of the print engines has a working space 16 or 17 and a movable one Element which is formed by an end 18 or 19 of the slide piston. These motors are powered by a

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actuated flowable drive medium, which is fed to the motors under a controlled pressure by a manually operated pressure-grading auxiliary control slide valve 21 with a closed center. This auxiliary spool valve has an inlet chamber 22 which is connected to a source 23 for receiving oil under a substantially constant low pressure, for example about 18 kgf / cm (250 psi). This auxiliary control slide also has a pair of outflow chambers 24 and 25 which are permanently in communication with the gate container 5, and a pair of motor openings 26 and 27 which are connected to the working spaces 16 and 17 of the controlled motors. The pressures at the motor openings 26 and 27 are varied by a valve body 28 which reciprocates in a valve bore 29 and which has a set of three narrow full parts 31 »32 and 33 or 34, 35 and 36 for each motor opening and with a set of three circumferential grooves 37 is formed larger and _T 38. 39 The middle full part 32 or 35 of each set fits into the slide bore 29, but the remaining full parts are smaller in diameter so that an annular opening is created between each of the full parts and the slide bore wall.

When the slide body 28 is in the illustrated neutral position, the motor openings 26 are and 27 separated from the inlet chamber 22 by the solid parts 32 and 35 respectively and they have substantially through the slide grooves 37 and 39 a free connection to the outflow chambers 24 and 25 · therefore takes place in this position through both motor openings a drain to the storage container 5- When the valve body is pushed to the left the full part 36 works with the wall

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the slide bore 29 together to restrict the flow from the motor opening 27 to the discharge chamber 25, and the full portion 35 progressively opens a supply path from the inlet chamber 22 to that engine port through the slide groove 38 and that formed by the full part 3'4- annular opening leads. With continued such movement, the full portion 35 begins the outflow path to close that of the motor opening 27 to the discharge chamber 25 through that formed by the full part 36 annular opening leads. This action increases the pressure at the motor port 27 relative to the pressure at the motor opening 26, since during this displacement the last-mentioned motor opening through the discharge chamber 24 remains switched to the reservoir towards the drain. The maximum control pressure is generated when the full part 35 moves to a position to the left of the engine opening 27, thereby effectively opening the engine separates from the discharge chamber 25. The size of this print is in. essential to the supply pressure in the -Inlet chamber 27 the same. Thus, this condition forms the effective end of the pressure gradation to the left Stroke of the slide body 28. In the same way, a movement of the slide body directed to the right increases 28 from the neutral position the pressure at the motor opening 26 compared to the pressure at the motor opening 27 · Am effective The end of this pressure-grading stroke is the motor opening 26 from the adjacent discharge chamber 24 through the full one Part 32 is separated and it is subjected to a pressure which is substantially the supply pressure in the inlet chamber 22 corresponds.

The leftward movement of the main valve piston 2 is adjusted by an adjustable stop -

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borders. Either this adjustable stop prevents a displacement of the slide piston from the drive position into the distribution or he leaves such a thing Shift to. This is only done in agreement with the amount by which the slide body 28 is shifted to the right from its neutral division is. The stop has a piston 41 which can be moved back and forth and which is aligned with the slide body 2. The piston 41 carries a plate 4-2, which serves as a seat for the collar 13 serves as the centering spring. The stop piston 4-1 responds to the pressure in a control chamber 43 and he is between the illustrated active position in which his head 44 rests against a housing shoulder 4-5, and movable to an inactive position in which the plate 4-2 rests against a housing shoulder 4-6. The plate 4-2 rests against the end 19 of the slide piston 2 when the stop piston is in its active position and the spool 2 is in a position for a driven downward movement. The plate 42 also rests against the end 19 of the slide piston 2 when the piston 4-1 is in its inactive position and the spool 2 is in its AbIaufstellung. From this "it follows that the Movement range of the stop piston 4-1 the way between the position for a driven downward movement and the discharge position "of the spool 2 corresponds. The control chamber 43 is controlled by a selection slide put under pressure or switched to drain, which is located in the auxiliary control slide 21 and from the full part 35 of the valve body and a cooperating therewith There is a control opening 47 which is arranged between the inlet chamber 22 and the motor opening 27 is and with the control chamber 43 in connection

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stent. The axial position of the control opening 4-7 is like this selected that they are about the effective, left and pressure-grading strokes of the slide body 28 directed to the right are exposed to the pressure in the inlet chamber is. The effective range of motion of the stop piston 41 is slightly larger than the effective range of motion of the end 18 of the slide piston 2. Therefore, the stop piston 41 during normal activity, the remote control system held in the active position, even if the controlled motor 14- is exposed to the maximum control pressure. On the other hand, when the valve body 28 is pushed to the right beyond the pressure-grading area, the full part 35 goes over the Control opening 4-7 away. This causes the control opening 4-7 over that formed by the full part 36 Opening, the TJmfangsnut 39 and the discharge chamber 25 to the reservoir 5 is switched to drain. This activity builds up the pressure in the control chamber 4-3 away. This enables the controlled motor 14- , the slide piston 2 and the stop piston 4-1 to move to the drain or inactive position.

The slide body 28 of the auxiliary control slide 21 is equipped with a centering spring 48 which presses the slide body 28 into the neutral position. About that In addition, the slide body 28 is provided with a detent mechanism that resiliently engages the slide body holds certain positions and the operator a so-called feeling or a warning regarding the> Fact is that further movement of the slider body will cause the spool 2 to move into the drain position. The notch mechanism has three rows of at the same angle to each other

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arranged balls 49 and a pair of in the slider body 28 formed grooves 51 and 52 for receiving of the balls. The balls are radially inward against the surface of the slide body 28 the conical cam surface of a reciprocating Sleeve 53 pressed. The sleeve 53 is pressed in the axial direction by a helical compression spring 54- towards the balls. -When one of the grooves 51 or 52 is aligned with the balls, the balls will move into that groove and they hold the slide body 28 in this position against the pressure force exerted by the centering spring 48. The positions of the grooves 51 and 52 are chosen so that the first groove with the balls 49 is aligned when the Slide body 28 is located at the effective limit of the pressure-grading stroke directed to the left. the second groove is aligned with the balls when the slide body 28 moves to the right into the position has been, in which the full part 35 switches the control port 47 to drain. These positions agree the raised position or with the downward division of the spool 2 match.

It should be noted that the groove 52 in the valve body 28 is limited to receive the balls on the right side by a narrow full part 55, which with the Balls 49 comes into engagement and which pushes the balls outward against the pressure of the spring 54 when the slide body is pushed into the position in which the groove is aligned with the balls. This cam action between the full part 55 and the balls increased instantly the resistance to the movement of the valve body. This notifies the operator that a further movement of the valve body the valve piston

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will cause to move to the expiration position.

When the control system described above is in operation and the valve body 28 is taking its The neutral position shown is the motor openings 26 and 27 of the auxiliary control slide 21 and the associated ones Working spaces 16 and 17 of the controlled motors to the storage container 5 switched to expiration. The centering spring 7 therefore holds the slide piston 2 in its neutral position and the cylinder 6 remains hydraulically blocked. Since the control port 47 at this time the supply pressure in the inlet chamber 22 of the auxiliary control slide 21, the stop piston 41 is in the shown active position held.

When the operator operated the cylinder 6 Desires to lift the load, she pushes the slider body 28 to the left in order to apply the pressure at the motor opening 27 ′ and in the working space 17. As a result, the controlled motor moves the spool 2 to the right, specifically first against the opposite action of the spring 7 and then against the common resistance of this spring 7 and the spring 8. The path over which the slide piston moves 2 moves depends on the pressure supplied to the working space 17 and this pressure in the working space 17 in turn depends on the displacement of the slide body 28. In this way the operator can monitor the dimensioning effect of the direction control slide 3 and accordingly also the speed of movement by a corresponding actuation of the slide body 28 of the cylinder 6. When the slide

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upper body 28 over its full stroke Ms in the through the locking position formed by the groove 51 is displaced, If the working chamber 17 is subject to the full delivery pressure of the source 23, and the motor 14 moves the slide piston 2 all the way into the lifting position. This activity completely closes the open in the middle Away and it directs the entire delivery rate of the pump 4 into the working space 6a. Therefore, the cylinder 6 moves at the maximum speed.

When the cylinder 6 has moved the load to the desired position, the operator pushes the slider body 28 back to the neutral position shown. This movement of the valve body builds up the pressure the motor opening 27 ″ and in the working space 17, so that the centering springs 7 ″ and 8 set the spool 2 return to its neutral position.

The cylinder 6 can through into the downward position a hydraulic drive can be driven by the slide body 28 from its neutral position to the right is moved. This displacement of the slide body 28 increases the pressure at the motor opening 26 and the controlled motor 14 can follow the slide piston 2 move left against the opposite action of the compression springs 7 and 8. As already described above, depends the dimensioning effect of the directional control slide 3 and, accordingly, the speed of the cylinder 6 from the path over which the slide body 28 has been moved from its neutral position. If the valve body 28 approaches the limit of its pressure-grading range, that is, immediately before the full one

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Part 55 comes into engagement with the balls 49, the pressure at the motor opening 26 is so high that the motor 14 can move the spool 2 into the position for a driven downward movement. Therefore, when the valve body 28 actually reaches this limit and the working space 16 is exposed to the full delivery pressure of the source 25, the displacement force generated by the motor 14 becomes greater than the comparable force for holding the valve piston in the position for a driven downward movement. With this arrangement, the operator can be certain that the spool 2 is in the position for driven downward movement when he feels the sudden increase in the resistance to movement of the slide body, regardless of the adverse effects of tolerances or operating conditions Cooperation of the full part 55 and the balls 49 is to be ascribed.

Over the normal range of motion of the slide body 28, the control opening 47 is constantly at full pressure exposed, "that in the inlet chamber 22 of the auxiliary control slide 21 is available. Therefore, the stop piston 41 is in the illustrated active position held, and the spool 2 is driven to move to the left beyond the position for a Downward movement prevented.

When a drain operation is desired, that is, when a rapid lowering of the load is to be carried out from a raised position, the operator increases the displacement force which he exerts on the. Slide body 28 exercises. This makes the full part

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caused the balls 49 to be pushed outward and the To enable the slide body to move into the locking position formed by the groove 52. These Displacement of the slide body does not change the pressure at the motor opening 26, since this opening is already the Supply pressure in the inlet chamber 22 is subject. However, this shift causes the full portion 35> into a position to the right of the control opening 47 to move and thereby switch the control opening 47 to the storage container 5 to drain. That means, that the pressure in the control chamber 43 is reduced. There in the position for a driven downward movement, both the collar 13 and the slide piston 2 abut against the stop plate 42, an emptying of the chamber 43 allows the motor 14, immediately the slide piston 2 and to move the stop piston 41 to the left into the drain position or into the inactive position.

When the slide body 28 is finally returned to its neutral position, the control opening 4 ¹ ^ is pressurized again and the motor opening 26 is switched to the storage container 5 to drain. The pressure in the control chamber 43 therefore pushes the stop piston 41 back into the active position, and the centering springs 7 and 8 guide the slide piston 2 back into its neutral position.

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Claims (1)

Claims / TI) Actuated by a pressure of a flowable medium Remote control system with a v controlled pressure motor adjusted power output part, with a spring acting in the opposite direction on the motor and with a control circuit, one of the auxiliary control spools, which can be moved from a neutral position, to supply the controlled one Motor with a variable pressure, characterized by a with the power output part (2) cooperating stop (41) movable between an active and an inactive position, in which it enables the controlled motor (14-) to the power delivery part (2) via a normal or to move over a larger range of motion, and by actuating the stop (41) on the Movement of the auxiliary control slide (21) responding device (14.55 »43.47) for setting the stop (41) into the active position when the auxiliary control slide (21) is in the normal range of motion is located, and in the inactive position when the auxiliary control spool (21) has been moved beyond the normal range of motion. 2. Remote control system according to claim 1, characterized in that that the device for actuating the stop has a stop pressure motor (41,43) for a has flowable medium and a selection valve (35,47) which is actuated by the auxiliary control slide (21) is and that serves the stop motor (41,43) one or the other of two different 3098 5 0/0322 Suspend pressure levels, depending on whether the auxiliary control slide (21) is in its normal range of motion or beyond this normal range of motion. 5- remote control system according to claim 2, characterized in that the device for actuating the stop also has a controlled pressure motor (14) that the stop motor (41,4-3) is effective to the stop to hold in an active position when the stop motor (41, 43) is the higher of the two different Is exposed to pressure levels, and that the stop motor (41,43) is effective when it is the lower of the two pressure levels to enable the controlled motor (14) to hit the stop to move into the inactive position that the selector valve (35 »47) the stop motor (41,43) exposed to the higher of the two pressure levels when the auxiliary spool (21) is in the normal Movement area is located, and the stop motor (41,43) exposes the lower pressure level when the auxiliary control spool (21) over the normal range is moved out, and that the auxiliary control slide (21) the pressure in the controlled motor (14) raises from a minimum when it is moved out of the neutral division. 4. Remote control system according to claim 3 »characterized that the auxiliary control slide (21) is the controlled Motor (14) exposed to a maximum pressure at the end of the normal range of motion and this Maintains pressure when the pilot spool is moved beyond the normal range. 3 0 9850/0322 5. Remote control system according to claim. 3, characterized in that that the spring is a helical compression spring (8) which is provided with a seat (4-2) of the stop is held, and that the force applied to the seat (42) by the spring (8) causes the stop pushes into the inactive position. 6. Remote control system according to claim 3? marked by a spring (48) which allows movement of the auxiliary spool (21) a resistance from its neutral position opposed, and by means (49,55) for applying an additional resistance force the auxiliary control slide (21), which are overcome must to move the slider beyond the normal range of motion. 7 · Remote control system according to claim 2, characterized in, that the power delivery part (2) is a slide piston of a hydraulic control slide 43), that by the controlled pressure motor (14) in one direction from a neutral pitch to a position for a driven downward movement and then in a drain position is displaceable that the stop has a reciprocable piston (41) adjacent one end (19) of the spool (2) is arranged and is aligned in the axial direction with the slide piston (2) that the stop also has a pair of stops (44,45; and 42,46) that the axial movement of the piston (41) to the Limit the spool (2) towards and away from it and thereby the active or inactive position form that the parts are arranged so that the 4ass 309850/0322 Slide piston (2) rests against piston (41), when the spool (2) is in position for a powered downward movement and the piston is in position is in the active position, and also when the spool (2) is in the distribution and the piston (41) is in the inactive position that the controlled motor (14) is the opposite End (18) of the slide piston (2) and an associated working space (16) comprises that the The device for actuating the stop has a controlled motor (14) which runs over the slide piston (2) acts to move the piston (41) to the inactive position, and that the device to actuate of the stop has a stop motor which has the piston (41) and an associated working space (43) and which serves to keep the piston (41) in the active position that the auxiliary control slide (21) a supply passage (22) and outflow passages (24,25) »one to the working space (16) of the controlled motor (14) has motor passage (25) and a movable element (28), that in reverse the flow paths connecting the motor passage (25) with the supply passage (22) and connect the discharge passages (24,25), throttling and thereby gradually the pressure in the engine passage (25) lifts when element (28) moves out of its neutral position, and that the selector valve one of the working space (43) of the impact motor leading control passage (47) and sections (35 * 38,39) of the movable element (28) of the Auxiliary control slide (21), which are used to Control passage (47) with the supply passage (22) in the normal range of motion of the element (28) 309850/0322 to connect, and to connect the control passage (47) with the discharge passages (24,25), if the element (28) is moved beyond the normal range of motion. 8. Pernsteuersystem according to claim 7> characterized in that the spring is a helical compression spring (8) which moves the slide piston (2) into its neutral position pushes out and has a seat (42) carried by the piston (41). 309850/0322