FI121533B - Type of device - Google Patents

Description

Blow the device

Background of the Invention

The present invention relates to a percussion device which is movable longitudinally with respect to the body of the impactor and which comprises a working chamber and a transmission piston movably mounted therein for axially compressing the tool with the in the material to be broken through the tool, the inlet and outlet ducts for supplying pressure fluid to and from the is-10, and a control valve having a movably mounted coupling member having at least one channel for alternately engaging said inlet and outlet ducts and, respectively, to release from the impactor the pressurized fluid acting on the piston.

In the impactor subject of the invention, a tension pulse is obtained by applying a piston to a transmission piston in a separate working chamber, preferably relatively suddenly. The effect of pressure pushes the transmission piston toward the tool. As a result, the tool is compressed to form a tension pulse in the tool, which passes through the work-tool and is exposed to breakage when the tool blade contacts a stone or other hard material. The impactor may be used to control its impact action by a rotary or reciprocating movable switch member typically having successive openings which alternately open the connection from the pressure source to the impact piston 25 and from the transfer piston to the pressure reservoir, respectively. Known solutions

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ς is generally a problem with device efficiency. Although the efficiency has been improved by various solutions, it is always advantageous if it can still be increased. Also, adjusting the length and amplitude of stress pulses is not easy in all solutions and the aim is to make the weather as easy as possible. 30 is always the goal.

Brief Description of the Invention

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It is an object of the present invention to provide an impact device which provides an improved efficiency and can adjust the length and amplitude of the stress pulse as desired. The impactor 35 according to the invention is characterized in that it comprises a movable shut-off element located in each of the pressure conduits between the control valve and the transmission piston and having a mechanical stopper for limiting the movement of each closing element towards the transmission piston at the same time stops the flow of pressure fluid in the pressure fluid duct from the control valve to the transmission piston so that the movement of the transmission piston towards the tool is stopped before the switch member closes the pressure connection between the supply channel and the pressure source.

The idea of the invention is that the formation of a stress pulse is accomplished by using a separate closing device of mechanically limited motion travel to stop the flow of pressure fluid in the direction of the transmission piston, whereby the length of the stress pulse is determined by the time of movement of the closing member.

An advantage of the invention is that the length of the stress pulse can be adjusted without substantially reducing the efficiency. In practice, the efficiency is clearly better than the known solutions because the opening time of the control valve can be made longer than current solutions. Also, the shape of the stress wave generated in this manner is advantageous because the opening of the control valve increases continuously with pulse formation and the opening can be dimensioned so that it is at its maximum when the stress pulse stops, i.e., when the control valve is fully open. In this way, the pressures of the working chamber acting on the transmission piston are thus obtained to the greatest extent of the stress wave just at the final stage of pulse formation. A further advantage of the invention is that the length of the tension pulse can be adjusted either by adjusting the movement length or time of the closing member or the pressure of the directly applied pressure fluid.

BRIEF DESCRIPTION OF THE DRAWINGS V The invention is explained in more detail in the accompanying drawings, in which: Fig. 1 schematically illustrates the prior art impact device ee 30,

Fig. 2 schematically shows an embodiment of the invention, c Fig. 3 schematically shows an embodiment of the invention as

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Fig. 2 is a cross-sectional view of the line B-B in Fig. 2 shows some curves illustrating the operation of the impactor according to the invention;

Figures 5a and 5b schematically illustrate other embodiments of the invention,

Figures 6a and 6b schematically show another detail of an embodiment of the invention, Figures 7a and 7b schematically represent further embodiments of the invention, and

Figures 8a and 8b schematically illustrate still further embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION 10 Fig. 1 is a schematic sectional view of a prior art impactor 1 having a body 2 having a working chamber 3 and a working piston 4 within the working chamber 3. The piston 4 is located parallel to the tool 5 and can move axially. so that the transmission piston 4 contacts at least at the start of the tension pulse formation and during its formation 15 directly through the tool 5 or indirectly via a known drill bit attached to the tool. On the side opposite to the tool of the transmission piston 4 is a pressure surface facing the work chamber 3. To generate a tension pulse, pressurized pressure fluid is supplied to the working chamber 3 from a pressure source such as a pump 6 via an inlet duct 7 via a control valve 8. The Oh-20 distribution valve has a movable switch member 8a having one or more channels as shown in the figure, such as openings or grooves 8b. As the switching member 8a of the control valve 8 moves, the pressure fluid can be exposed through the apertures or grooves 8b to the transmission piston 4 and, respectively, the pressure fluid acting on the transmission piston 4 when the switching member 8a is still moving. An excitatory pulse is formed when the pressure of the pressure fluid at work

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5 puts the transmission piston 4 into the tool 5 and thereby compresses the tool 5 against the material to be broken. As the pulse passes through the tool 5 after passing its tip, such as, for example, a drill bit, it is obtained in a manner known per se to break material, such as stone, to break it. When control | The switch member 30 of the valve 8 closes the entry of the pressurized fluid into the impactor and then releases the pressurized fluid acting on the piston 4 through the outlet duct 9 to the pressure fluid reservoir 10, stopping the pulse and short This is repeated as the movement of the coupling member 8a of the attached valve 8 alternately engages the pressure acting on the transmission piston and correspondingly allowing the pressure to release, whereby a series of successive voltage pulses are continuously formed as the member 8a moves continuously.

During operation of the impactor, it is pushed in a manner known per se with a feed force F toward the tool 5 and towards the material to be broken.

5 In order to push the impactor, it is possible, in a manner known per se, to use only a working boom or a feed beam mounted on the boom with feeding equipment. These per se are generally well known to those skilled in the art and therefore need not be explained in further detail. In order to return the transmission piston 4, the pressure medium between the tension pulses 10 may be supplied to the chamber 3a, if necessary, or the transmission piston may be returned by mechanical means such as a spring or by pushing the impactor into the drilling direction. The tool may, in a manner known per se, be separate from the piston or integral with the piston. The piston may also be integrated with the pol-15 cuff so that the drill bar is screwed in a manner known per se to the threads at the end of such an assembly.

Fig. 1, the case is a control valve 5 with eight tool coaxially rotatably moving switch member 8, which is rotated about its axis direction of arrow A suitable spin of such power transmission schematically illustrated moottoril-20 la 11 by a broken line means Alternatively, the switch member 8 is turned rotatably back and forth using a suitable mechanism. The rotatably movable coupling member may also be located in another way, for example mounted on the frame 2 on the side of the work chamber 3. Instead of a rotatably movable coupling member, the control valve 8 may also utilize a reciprocating movable coupling member. Further, in all cases, a control valve may be used, the switch member of which has only one channel for supplying pressure fluid to and from the working chamber. Preferably, the switching valve 8 of the control valve 8

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However, the channel 8a has a plurality of parallel channels.

t Fig. 1 further illustrates a control unit 12 which may be coupled to a control 30 to control the speed of a control valve or a reciprocating control | the speed of movement of the valve by means of control channels or signal lines 13a and 13b, c. Such adjustment can be accomplished by a variety of techniques known per se using desirable parameters such as drilling conditions, e.g.

Fig. 2 schematically illustrates a principal embodiment of the invention. Only a portion of a control valve 8 with a reciprocating coupling member 8a and a body 2 of the impactor is shown therein. It has a separate closing member 14 between the control valve 8 and the transmission piston 4, which moves in a valve 15 in the pressure fluid conduit. A tension pulse is generated by the fact that the pressurized pressure fluid is directed by means of the control valve 8 to flow towards the transmission piston 4, whereby the closing member moves substantially with the flow in the duct. In this situation, substantially the same pressure is applied on both sides of the closure member. As a result, the transmission piston 4 moves towards the tool 5, squeezing it, resulting in a tension 10 pulse being formed in the tool. The generation of the stress pulse continues until the blocking member 14 stops at a mechanical barrier to its movement and at the same time closes the flow of pressure fluid towards the transmission piston 4. By varying the travel distance of the closing member 14, the length of the stress pulse can thus be adjusted.

After the tension pulse has been generated, the control valve switch member 8a 15, while in motion, connects the connection between the pressure valve channel 8 between the control valve 8 and the transmission piston 4 to the pressure return channel 9, thereby releasing the piston 4

Fig. 2 illustrates in principle a solution in which the pressure acting time on the transmission piston depends on the movement distance s of the closing member 14, which is a mechanically limited possible travel of the closing member 14 in the direction of the transmission piston 4. In the case illustrated in Fig. 2a, the closing member 14 stops when it contacts the bottom surface of the pressure fluid compartment 3b. Because the closure member 14 is substantially equal to the pressure fluid-25 channel in which it moves, it also stops the flow of pressure fluid toward the transmission piston 4 when it stops. The tension pulse is then at its peak. The opening time of the coupling member to the supply pressure can be significantly

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^ longer than the movement time of the occluding member, i.e. the time of formation of the stress pulse.

T Excitation pulse formation begins as soon as the pressurized fluid passes through the opening 7b 8b only in the conduit 30 to penetrate the pressure fluid duct 15, thereby affecting | As the pressure in the pressure fluid duct 15, and thus the working cd, increases the pressure in the fluid fluid, the pressure will increase as the switch member 8a moves and the opening 8b moves o more to the channel 7 and the pressure fluid duct 15 to open the flow port. ^ 35 ever bigger. Advantageously, the travel s of the closure member 14 is dimensioned such that movement of the closure member 14 stops when the flow passage through the control valve 6 is at its maximum, i.e. the opening 8b is completely open at the pressure fluid conduit 7 and pressure relief conduit 15 and thus the control valve 8 is fully open.

Fig.3 schematically shows a section B-B in Fig. 2, in one embodiment of the invention, which has several pressure fluid channels instead of a single pressure fluid channel and a closure member 14, and correspondingly a number of closure members 14 in each embodiment. 4 so that the supply of pressure fluid can be carried out as easily and efficiently as possible. Although, by way of example, eight closing members are shown, the number 10 may be one or more, including more than eight, if, for constructive reasons, it is considered necessary.

Fig. 4 schematically shows pressure curves illustrating the operation of the impactor according to the invention. It shows the pressure (bar) of the pressure fluid in the horizontal axis and the length of the stress wave in milliseconds, respectively, on the vertical axis at two motion values of 15 different closing members. The areas Am, Ak and As mentioned in the formulas are shown, for example, in FIGS. 2 and FIG. 3.

The length of the resulting stress wave can be roughly estimated as follows. Assume that the transmission piston has a surface area of Am = 4500 mm2 and a tool surface area of Ak = 1000 mm2. The supply channels (10 pieces) have a surface area of 20 As = 300 mm2. The genomic travel is limited eg s = 1 mm. If the pressure level p is used, then in theory, a stress wave having an amplitude σ = ^ ρ = 4.5ρ is produced (1)

Ak 25 o o In this case, the transmission piston will gain speed

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«V„ = - cr = ^ P, (2) o cp Akcp

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cc

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^ 30 where c is the speed of the stress wave in the tool and p is the density of the material. The corresponding flow in a single supply channel is

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o w AA2 q = -trv "> = T- ^ P (3) N AkNcp 7 and the mean velocity of the fluid in channel a A2 v = - = --— p (4)

^ As AkNAscpP

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When the duration of the stress wave is tp and the blocking member moves at substantially the same rate as the liquid, the transition of the blocking member in the supply channel 10 is obtained by A2d xs = vnesJp = -— f - tp (5)

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When the motion xs of the closing element is limited to s, the pulse length 15 is obtained, ÄkNAscps / cx = Ai „(6)

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20 The numerical values given by positioning give ^ (7) '6.75 p o δ ^ The result also shows that the length of the stress wave is inversely proportional to the pressure; the higher the pressure, the shorter the pulse. Figure 5 shows the lengths of the stress wave at two different values of travel s at different pressure levels c. In other words, the pulse length can also be adjusted solely

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the impact pressure level.

Fig. 4 shows the curves calculated on the basis of the above for two travel distances of the different closure members, i.e. travel of 1 mm and 1.5 mm respectively. Fig. 4 shows that the length of the stress wave is greater the longer the distance traveled by the closure 14. Further, according to Fig. 4, the length of the stress wave is inversely proportional to the applied pressure pressure. Thus, by using 8 fixed travel distances with the closing member or members 14, the pulse length can be adjusted solely by the pressure of the applied pressurized fluid. If a shorter tension pulse is desired, the pressure is increased, whereby the closing member moves more quickly to shut off the pressure fluid flow, and correspondingly, if a longer tension pulse is desired, the pressure is shifted slower to shut the pressure fluid flow.

In practice, it is necessary for the pressure fluid in the working chamber of the transmission piston 4 to change, otherwise it will be allowed to overheat. It should also be borne in mind that in such a solution, there will always be some oil leakage despite the seals.

Figures 5a and 5b show some embodiments of the invention, where these aspects are taken into account. In these embodiments, a conduit 16 is provided through a closure member 14 having an opening in the projection 14a through which a small amount of pressurized fluid can flow from the pressurized fluid passage 15 to the working chamber 15 when the pressure is applied to the closure member 14. As the tensioning pulse progresses as the closing member 14 moves toward the pressure fluid space 3b, the projection 14a on the side of the closing fluid member 3b extends into a correspondingly shaped recess 3c, preventing the flow of pressure fluid 20 from the conduit 16 to the pressure fluid space 3b. Once the tension pulse has been formed, the transmission piston 4 and the closing member 14 return to their initial position as previously described, whereby the excess pressure fluid flowing into the pressure fluid space 3b and thus into the working chamber 3 is again discharged through the conduit 16. In the embodiment shown in Fig. 5a, the piston is reset to its initial position by utilizing the impact force of the impactor, whereby the propelling force pushes the impactor forward and the piston supported by the tool 5 remains in place as the impactor body protrudes into the tool 5. In this case

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The pressure fluid space 3a in front of the transmission piston 4 is connected to the pressure fluid reservoir by pressure 9 in a non-pressurized manner.

° 30 The coupling member 8a of the control valve 8 has a groove or the like | such as the opening 8c, which connects the pressure fluid channel 15 between the closing member 14 and the control valve 8 to the channel 17. The transmission piston 4, in turn, has an internal channel 18 which, as the transmission piston 4 moves towards the tool 5, opens the connection chicken-35 van 17. When the transmission piston 4 is pushed back to its original position with respect to the body 2 of the impactor 1, the pressurized fluid flows from the working chamber 3 first pushing the closure member 14 backwards and then through the channel 16 of the closure member 14 to the pressure fluid channel 15 and further through the channel 18. pressure fluid state 3a. When the transmission piston 4 has moved to its initial position, i.e. the position shown in Fig. 5a, the connection between the channels 17 and 5 18 is closed and the pressure fluid can no longer flow out of the work chamber 3. The transmission piston 4 is then hydraulically stopped in its initial position. Of course, the transmission piston 4 can also be mechanically stopped in its initial position, as shown in Fig. 5b. In this embodiment, the pressurized fluid may enter directly through channel 9 into the pressurized fluid reservoir 10.

Figures 6a and 6b show another detail of an embodiment of the invention. It has a solution suitable for supplying pressurized fluid and equalizing the pressure peaks generated by the reflection of the tool. In this embodiment, the closing member 14 is formed of a spherical body, which in itself can be applied to all embodiments of the invention. In the situation illustrated in Fig. 6a, tension pulse formation has ceased when the closing member 14 has stopped at the shoulder 20 and the closing member and the counter surface together prevent the flow of pressure fluid. The valve member 15a of the closure member 14 has a counter-valve 21 coupled to the valve member 15a of the closure member 14 so that, depending on the position of the closure member 14, it is connected to either the pressure fluid conduit 15 or 20. During operation of the impactor, the valve member 21a of the non-return valve 21 is subjected on one side to the operating pressure p of the impactor which pushes the valve member 21a to shut off the flow of pressure fluid from the pressure fluid conduit 15 and the pressure fluid space 3b respectively.

In the case of Fig. 6a, at the end of the tension pulse formation, the closing member 14 is tight against the counter surface of the shoulder 20 and closes the pressure fluid flow together with the counter surface. Then there is a valve space

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15a connected to the pressure relief valve 21 but connected to the pressure fluid duct 15. When the flow of the pressure fluid into the pressure fluid duct 15 stops abruptly, a strong pressure pulse is formed, the pressure value of which may exceed the normal | paint pressure significantly. On the opposite side of the non-return valve member 21a there is a normal operating pressure p, whereby the pressure exerted by the pressure peak pushes the non-return valve valve 21a out of its closure position, thereby allowing the discharge peak to discharge into the normal supply pressure.

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Fig. 6b, in turn, shows a situation in which the transmission piston 4 has returned after the formation of a stress pulse and the closing member 14 has returned to its initial position. In this situation, the opening leading to the check valve 21 in the valve space 15a is connected to the chamber 3 of the working piston 5 of the transmission piston 4 via the pressure fluid space 3b. When the stroke frequency of the impactor is dimensioned to suit the tool and other conditions, the stress wave reflected from the stone to the tool returns to the transmission piston 4 at this very moment. This stress wave causes a pressure peak in the working chamber 3 and associated pressurized fluid compartments which also exceeds the normal operating pressure p of the impactor. The effect of the pressure peak 10 on the check valve 21 causes the valve member 21a to open and discharge to normal operating pressure without damaging the At the same time, at least part of the energy of the reflected stress wave is recovered as hydraulic energy.

It is advantageous for the invention that the distance between the closure member 14 and the transmission piston 4 is as short as possible in order to minimize the loss of pressure fluid flow.

Figures 7a and 7b show further embodiments of the invention. They use a closure member 14 which has a smaller cross-section than the surrounding valve space 15a. Thus, both the supply of the pressure fluid 20 and the return flow allow the pressure fluid to flow through the gap between the closure member 14 and the valve chamber 15a. Thereby, the pressure fluid in the working chamber 3 is allowed to change to some extent and is cooled therewith. In these embodiments, the flow of pressure fluid stops when the conical or curved, e.g. spherical, surface 14b of the closure member contacts the e.g. conical or concave sealing surface 15b at the end of the valve space 25a.

Figures 8a and 8b show yet another embodiment of the invention. In it 5, a separate pre-guided auxiliary is used to effect the piston return movement.

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^ valve.

In this solution, the discharge of pressure fluid from the work chamber 3 is controlled by auxiliary valve 23, which in turn is controlled by a switch member 8a of the control valve 8.

| The auxiliary valve 23 has a groove or opening 23a which allows the auxiliary valve 23 to connect the cd connection from the duct 15 to the outlet duct 9. Further at one end of the auxiliary valve 23 opposite to the duct 22 there is a projection 23b having a smaller surface area than the a Area of the 22-sided head.

™ 35 This end of the projection 23b is influenced by the pressure of the pressure fluid, preferably the pressure in the channel 7.

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After the previous tension pulse has been formed, the transmission piston remains in its tool-side position. The stress pulse after forming the moving clutch member by the arrow 8a A and connects the pressure fluid supply duct 7 an auxiliary valve passage 22. Thus the auxiliary valve 23 moves against its ulokkee 5 to 23b acting pressure force exerted and the connection channel 15 opens into the outlet passage of the auxiliary valve 23 opening 23a through 9 of Fig. 8a. Thus, the pressure fluid can flow from the duct 15 into the outlet duct 9 and, under the action of a force acting on the transmission piston 4, the transmission piston 4 begins to move back to its initial position by pushing the pressure fluid out of the working 10 chamber.

The pressure fluid can then flow from the channel 15 through the opening 23a of the auxiliary valve 23 to the outlet channel 9. Under the effect of the force acting on the transmission piston 4, the transmission piston 4 begins to move back to its initial position pushing the pressure fluid out of the working chamber 3. As a result, the closing member 14 moves rearwardly in the direction of the channel 15 until its movement is stopped as previously described. The transmission piston 4 is then in its rearmost position and stops there.

Prior to the next generation of tension pulse, the auxiliary valve channel 22 engages through a groove 8c of the coupling member 8a to a channel 15 and further through auxiliary valve channel 23a to a discharge channel 9. As a result, the pressure in the a 8b.

The switch member 8a moves further in the direction of arrow A, the pressure switch 25 of the liquid pressure in the channel 7 through opening 8b to affect välitysmän-4 and a stress pulse is formed.

Figures 8 and 8b further show a solution where the piston 4 is integrated

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± with a well-known drill bit. The part of piston 4 corresponding to this drill bit is denoted by 4a. The part 4a is provided with a thread not known to you in which the tool 5 is screwed in, not shown. Section 4a may also be | provided with a toothed or other suitable arrangement therewith, and therewith a cd for rotating the tool 5 with a rotating motor known per se, not shown.

Part 4a comes out of the front end of the impactor body 2 correspondingly to the drill bit, so that the tool can be easily screwed in and out respectively.

The invention has been described above in the specification and drawings by way of example only and is not limited thereto. The various details of the embodiments may be implemented in different ways and may be combined with each other. Accordingly, the details in the various figures 1 through 3b and 5a to 6b can be combined with one another in a different practical implementation as needed. The rotation 5 or the reciprocating movement of the switching member 8a of the control valve 8 may be performed in any manner known per se, mechanically, electrically, pneumatically or hydraulically. Although the control valve by the rotary coupling member 8a is exemplified in a form having a cylindrical valve member, it can likewise be realized in the form of a disk, conical or other similar form. Instead of the openings passing through the control valve switch member 8a, grooved channels formed in the switch member 8a may also be used. Also, the pressurized fluid supply and discharge channels need not be on opposite sides of the switch member as long as they are at different positions. The closure member may also be smaller in cross-sectional area of the valve space, whereby its closure capacity 15 is based e.g. 6a and 6b in cooperation with the counter surface.

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Claims (9)

A percussion device in which a longitudinal movable tool (5) of the percussion device (1) can be mounted in its longitudinal direction and the percussion device (1) comprises a working chamber (3) and a shaft therein in the tool (5). direction movably mounted intermediary piston (4) to compress the tool (5) with a pressure of a pressure fluid acting suddenly on the intermediary piston (4) together in its longitudinal direction, so that in the tool (5) a voltage pulse in its longitudinal direction, which progresses through the tool for a material to be crushed, supply and discharge channels (7, 9) for conducting pressure fluid to and away from the impact device (1) and a control valve (8) with a movably mounted coupling means (8a), which at least one duct for coupling said supply and discharge ducts (7, 9) alternately conducts pressure fluid from the feeder duct (7) along at least one pressure fluid duct to act on the conveyor piston (4) and correspondingly One way of releasing pressurized fluid acting on the conveyor piston (4) from the impactor (1), characterized in that it comprises in each pressurized fluid duct between the control valve (8) and the mediator piston (4) located in the pressurized fluid duct. movably mounted locking member (14) and having a mechanical limiter for limiting each movement of a locking member (14) against the mediator piston, so that when the locking member (14) stops at the limiter, it simultaneously stops the flow of pressure fluid therein in the pressure fluid. from the control valve (8) to the intermediate piston (4), so that movement of the intermediary piston (4) to the tool (5) stops before the coupling means (8a) closes the pressure connection between the feeder duct (7) and the pressure source. O The impact device according to claim 1, characterized in that the movement of the locking member (s) (14) is limited so that the movement of the mediator piston (4) towards the tool (5) is stopped substantially at the same moment as the control valve (8) is completely open. ir 30 The impact device according to claim 1 or 2, characterized in that the limiter is a limiting surface located in the direction of movement of the locking member (14) on the side of the intermediate-piston (4), against which the locking member (14) is disappointed by the influence of the pressure fluid. O 4. The impact device according to claim 3, characterized in that the limiting surface together with the locking means (14) shuts off the flow of pressurized liquid towards the intermediary piston (4). 17 5. Impact device according to any of the preceding claims, characterized in that the locking member (14) has a protrusion (14a) on the side of the intermediate piston (4), so that where the locking member (14) is in its rearmost position, there is a clearance between the protrusion (14a). ) and the surface adjacent the locking member (14) on the side of the mediator piston (4), the surface of the mediator piston (4) at the corresponding location having a depression (3c) substantially with the shape and size of a protrusion (14a), in which the protrusion (14a) ), and that the locking member (14) has a channel extending through the conductive and adjacent the burst (14a), along which the pressurized liquid will flow into the working chamber (3) and, correspondingly, back from the working chamber, when the burst (14a) is the outside depression (3c). The impact device according to any of claims 1-4, characterized in that the locking means (14) is spherical. The impact device according to any one of the preceding claims, characterized in that it has a contrast valve (21) and on the movement distance of the locking means (14) there is at least one opening which interferes with the contrast valve (21), so that the the locking member (14) is in its prime position, the pressure fluid channel coming from the control valve (8) through the at least one opening communicates with the contrast valve (21), and where the locking member (14) is in its rearmost position, the working chamber (3) having at least one opening in communication with the contrast valve (21), and that on the contrast valve (21) and the valve member acts under the operating pressure of the impact device (1), the impact pressure of the impact device (1), which disables the valve means to shut off the flow of pressure fluid from the working chamber (3) and correspondingly from the pressure fluid duct coming from the control valve (8), where their pressure is at most equal to the operating pressure. 8. Impact device according to any of the preceding claims, characterized in that the supply and discharge channels (7, 9) are coupled to direct pressure fluid into and away from the coupling means (8a) and that the coupling means (8a) exhibit at least a channel for coupling the supply and discharge channels (7, 9) in turn to conduct pressure fluid from the supply channel (7) along at least one pressure fluid channel to act on the conveyor piston (4) and CD correspondingly to conduct pressure liquid acting on the supply piston (4). ) away from the striking device (1) via the coupling means (8a). σ> Section 9. Impact device according to any of claims 1-7, characterized in that the supply duct (7) is coupled to supply pressure fluid to the coupling means (8a), that it has a separate auxiliary valve (23) capable of coupling. 18 is directed to conduct pressure fluid acting on the conveyor piston (4) from the percussion device (1) to the discharge duct (9), that the coupling means (8a) has at least one channel for coupling the supply duct (7) to alternately conduct pressure liquid from the supply duct ( 7) along at least one pressure fluid channel to act on the mediation piston (4) and correspondingly at least one channel through which the pressurized pressure fluid will act on the auxiliary valve (23) to open the connection to the discharge channel (9) to release pressure fluid acting on the intermediate piston (4) away via the auxiliary valve (23). o δ (M oo o X and CL CD δ m σ> o o cv