Impact piston device for impact drill drives

Abstract

To provide an impact piston device.SOLUTION: An impact piston device for an impact drill drive is an impact piston movably implemented in a piston housing so as to reversible between a front hitting position and a back retracting position and having a front pressuring surface and a back pressuring surface, and it comprises an impact piston having a front pressure chamber and a back pressure chamber integrated with the piston housing, a hydraulic fluid feed, a hydraulic fluid drain, a first control device for coupling the back pressure chamber for an impact piston reverse movement with the hydraulic fluid feed and hydraulic fluid drain alternately and a second control device capable of adjusting stroke path of the impact piston in the piston housing. The first control device has a first control valve which can be actuated and the second control device has a second control valve which can be actuated and the first control valve and the second control valve are arranged in a valve housing in common.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an impact piston device for an impact drill drive, comprising: an impact piston movably mounted in a piston housing so as to be reversible between a forward striking position and a rear retracted position, the impact piston having at least one front pressure surface and at least one rear pressure surface, the impact piston having at least one front pressure chamber and a rear pressure chamber formed integrally with the piston housing; a hydraulic fluid feed, a hydraulic fluid drain, a first control device alternately connecting at least the rear pressure chamber for effecting a reversing movement of the impact piston to the hydraulic fluid feed and the hydraulic fluid drain; and a second control device capable of adjusting at least one stroke path of the impact piston within the piston housing, the first control device comprising an actuable first control valve and the second control device comprising an actuable second control valve, according to the preamble of claim 1. [Background technology]

[0002] Such impact piston devices are used in impact drill drives, which are required, inter alia, in earth and rock drilling machines, in particular in so-called anchor drills. An additional impact movement by the impact piston can thus be applied to the rotary-driven drilling tool. A good drilling progress is achieved in this way, especially in hard materials, especially when drilling lithic materials or in rock.

[0003] A typical impact piston arrangement for an impact drill drive can be found, for example, in US Pat. No. 5,399,633.

[0004] The known impact piston device comprises a piston or hammer mounted in a piston housing for axial movement between a front pressure chamber and a rear pressure chamber. One of the two pressure chambers is continuously hydraulically preloaded with hydraulic fluid via a first control device with a control valve. The other pressure chamber is alternately supplied with pressurized fluid and drained therefrom by the first control device with its control valve. When fluid is supplied to this pressure chamber, a large pressure surface of the impact piston causes an axial shift opposite to the preload direction. When the pressure chamber is drained or vented, a corresponding opposite movement occurs.

[0005] A second control device with a control valve is provided and is arranged separately from the first control device in order to vary the stroke length of the impact piston: by opening and closing various channels provided and by the action of ring-shaped grooves which are mutually axially offset with respect to the piston housing, various stroke lengths can be set for the impact piston or hammer.

[0006] These adjustments are always accompanied by a certain amount of time lag. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] German Patent No. 2635191 Specification (C3) Summary of the Invention [Problem to be solved by the invention]

[0008] SUMMARY OF THE PRESENT EMBODIMENT It is a basic object of the present invention to provide an impact piston arrangement having exceptionally efficient response characteristics. [Means for solving the problem]

[0009] This object is achieved according to the invention by an impact piston device having the features of claim 1. Preferred embodiments of the invention are set out in the dependent claims.

[0010] The impact piston device for an impact drill drive of the present invention is characterized in that the first control valve and the second control valve are disposed in a common valve housing.

[0011] The concept underlying the present invention consists in combining two control valves of two control devices in one valve housing, which in principle results in very short lengths of lines and channels for hydraulic liquid. In addition, the lines can be fixed in the housing, thus avoiding or minimizing the risk of leakage and damage, for example to loose pipelines or hose lines. The shortening of the lines and the resulting improved flow and the corresponding reduction in the liquid volume in the lines improve the response characteristics of the control arrangement comprising the two control valves. This also results in a more compact and robust design, since a faster and more efficient actuation and adjustment of the impact piston during operation is achieved.

[0012] In one preferred embodiment of the invention, the valve housing comprises a valve block into which the fluid lines and valve receptacles are formed, in particular milled, resulting in a particularly robust valve and control arrangement within the preferably metallic valve block, which is particularly resistant to vibration and external mechanical influences.

[0013] The lines are incorporated into the valve block as recesses, for example by milling. In an advantageous development of the invention, a cover plate is provided, by which the valve block containing the valve lines and the valve receptacles is closed. The cover plate is arranged on the valve block via suitable seals and is preferably screwed to the valve block in a liquid-tight manner. This preferred two-part housing design firstly allows for a particularly simple manufacture of a robust valve block and secondly allows for easy maintenance, since it is only necessary to remove the cover plate, i.e. the upper housing half, from the valve block, i.e. the lower housing half.

[0014] In one particularly advantageous embodiment of the invention, the ports for the hydraulic fluid feed, the hydraulic fluid drain, and the connection ports for the line connections to the piston housing are located on the valve housing, resulting in a particularly robust device, especially since only 3, 4, or 5 ports need be provided on the housing.

[0015] In principle, any suitable and necessary control valve can be arranged and positioned in the valve block. Particularly preferred here is the design of the first control valve as an actuable 3 / 2-way valve. This control valve can preferably be actuated by the action of an electrically actuable element, in particular an electromagnetically actuated element. The control valve can in particular have an axially displaceable control piston which can be displaced between its actuating positions by the action of an electromagnet.

[0016] In one particularly advantageous embodiment of the invention, the piston housing, in particular the rear pressure chamber, is alternately connected to the hydraulic feed and the hydraulic drain by the first control valve. In particular, a constant hydraulic fluid pressure is continuously supplied to the front pressure chamber, which is located closer to the striking face of the piston. Through the alternate connection of the rear pressure chamber via the first control valve, i.e. to the hydraulic feed on the one hand and to the hydraulic fluid drain on the other hand, a reversing movement of the impact piston can be generated by the action of a suitably designed annular working surface on the impact piston.

[0017] When the hydraulic feed is switched on, the impact piston has a correspondingly larger working surface in the rear pressure chamber, so that in the area of ​​the rear pressure chamber a force that is greater than the force acting on the correspondingly smaller working surface of the impact piston in the front pressure chamber can be applied to the impact piston. In this case, the hydraulic feed can be designed with an annular groove on the impact piston and / or the piston housing, so that when the impact piston is in a certain position, the pressurized fluid can flow from the front pressure chamber into the rear pressure chamber through the pressure channel that is formed, thus allowing a modification to the striking action. This is due to the fact that the pressures provided in the two pressure chambers are equal, e.g. due to the different sizes of the working surfaces, a greater force is applied by the pressurized fluid in the rear pressure chamber to the impact piston, which pushes the piston forward in a certain way and performs a striking action.

[0018] According to a further embodiment of the invention, the actuatable second control valve is preferably designed as a 3 / 2-way or 4 / 3-way valve. Like the first control valve, the second control valve can be electrically actuated by the action of an electromagnetically actuated element. In particular, the control valve can have an axially shiftable control piston which can be shifted between its operating positions by the action of an electromagnet. Alternatively, the control valves can also be actuated via a pressure channel.

[0019] In one particularly advantageous embodiment of the impact piston device according to the invention, the outlet of the second control valve is connected to a control line for actuating the first control valve, a direct control line between the two control valves can thus be provided, in which case a pressure change can trigger a control action.

[0020] According to a further variant of the invention, the inlets of the second control valves are respectively connected by lines to annular spaces in the piston housing, which can be formed by annular grooves on the impact piston itself and / or in the inner wall of the piston housing. In particular, a number of axially spaced annular spaces are provided to adjust the stroke length of the impact piston. Depending on the combination of the annular spaces, it is therefore possible to determine at which axial position of the impact piston a pressure channel and a pressure build-up in the rear pressure chamber are realized, which can initiate a forward striking movement of the impact piston.

[0021] According to a further embodiment of the impact piston device of the present invention, a control port for actuating the second control valve is preferably provided on the valve housing, in this way the second control valve can be actuated directly via the control port.

[0022] The impact drill drive according to the invention comprises at least one drill drive, which is provided with an impact piston device according to the invention, which is itself designed to drive in rotation a drilling tool, on which an axial striking movement can be exerted constantly or at specific times by means of the impact piston device.

[0023] In particular, according to the invention, the impact drill drive can be arranged on a carriage or on a mast of an earth or rock drilling machine, which can be used in particular for anchor drilling in specialist civil engineering works.

[0024] The invention will now be described in more detail with reference to preferred exemplary embodiments which are illustrated diagrammatically in the drawings, in which: [Brief description of the drawings]

[0025] [Figure 1] FIG. 2 is a schematic circuit diagram of an impact piston device according to the present invention; [Diagram 2] FIG. 2 is a hydraulic circuit diagram of the impact piston device according to the present invention. [Diagram 3] 1A-1C are diagrams showing various side views and various perspective views of a block-type valve housing provided for the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] In order to illustrate the operating mode of the impact piston device 10 according to the invention, a first circuit arrangement with a first control device 50 but without a second control device according to the invention is shown in Fig. 1. A shaft-shaped impact piston 20 is mounted inside a piston housing 12, which is shown only diagrammatically, so as to be movable in a reversible manner. A front striking side 22 of the impact piston 20 projects from the piston housing 12 and can be struck in a striking manner, for example on a drill drive shaft (not shown).

[0027] A forward first shoulder 24 and at least one further rearward second shoulder 28 are formed on the impact piston 20 in a generally known manner. The larger diameter shoulders 24, 28 are spaced apart from one another along the axial direction, and an annular space 15 having a smaller diameter is formed between each of two adjacent shoulders 24, 28. In the piston housing 12 having a cylindrical receiving chamber, a first forward pressure chamber 14 is delimited by the first shoulder 24, and a forward pressure surface 26 facing towards the forward pressure chamber 14 is formed on the first shoulder 24.

[0028] Within the receiving chamber of the piston housing 12, a rear pressure chamber 16 is formed rearwardly of a second shoulder 28 on which a rear pressure surface 29 is formed, facing towards the rear pressure chamber 16. What is essential for the operating mode of the impact piston device 10 is that the rear pressure surface 29 is larger than the front pressure surface 26, as is also clearly shown in FIG.

[0029] A hydraulic feed 30 of lines is provided for the reciprocating movement of the impact piston 20, which is shown in Figure 1 in its retracted position within the piston housing 12. Hydraulic liquid is drawn from a tank 42 by a hydraulic pump 32 and introduced under pressure into the hydraulic feed 30. The forward pressure chamber 14 is continuously supplied with pressurized hydraulic liquid through a first branch leading thereto. The action of hydraulic liquid in the forward pressure chamber 14 on the forward pressure surface 26 urges the impact piston 20 rearwardly towards its retracted position shown in Figure 1.

[0030] The hydraulic feed 30 in line further extends to a first control device 50 having a first control valve 52 with three ports and two valve positions. The first control valve 52 is therefore a 3 / 2 way valve.

[0031] In the first setting position shown in FIG. 1, hydraulic fluid is directed from the hydraulic feed 30 to the rear pressure chamber 16 in the piston housing 12. Due to the larger surface area of ​​the rear pressure surface 29 on the second shoulder 28, a larger force is exerted on the impact piston 20 along the striking side 22 than the counter force exerted by the pressure fluid in the front pressure chamber 14 on the front pressure surface 26. When the first control valve 52 is in this position, the impact piston 20 therefore moves forward and out of the piston housing 12, thus performing a striking movement. The valve position can be detected through a first control port 54 on the actuable first control valve 52, taking into account the pressure in the hydraulic feed 30 upstream of the first control valve 52. The pressure in the control line 57, i.e. the pressure entering the piston housing 12 at the edge of the front pressure chamber 14 and transmitted towards the first shoulder 24, can be detected through the control line 57 via the second control port 56.

[0032] By displacing the impact piston 20 forward towards the striking side 22, the control line 57 is blocked from the front pressure chamber 14. By further moving the impact piston 20 along the direction of the arrow shown in FIG. 1, the annular space 15 is connected to the vent line 59, which also leads into the piston housing 12. When the impact piston 20 is in the appropriate position, the annular space 15 can be vented via the vent line 59 towards the hydraulic drain 40 and thus to the tank 42. The annular space 15 is thus depressurized and eventually exhibits a reduced pressure. By further shifting the impact piston 20 along the direction of the arrow, a line connection between the vented annular space 15 and the control line 57 is established, and a corresponding pressure reduction is established in the control line 57. In this manner, the first control valve 52 can be switched by the second control port 56 of the first control device 50.

[0033] This switch places the control valve 52 in the second valve position, and pressure fluid is no longer directed through the first control valve 52 to the piston housing 12 through the hydraulic feed 30. In addition, the connecting line to the piston housing 12 is then connected through the first control valve to the hydraulic drain 40 and thus to the tank 42. In the rear pressure chamber 16, a noticeable pressure drop will eventually occur due to this venting and decompression switch to the tank 42. Therefore, due to the continuous feed of hydraulic fluid through the hydraulic feed 30 via the first branch, the pressure in the front pressure chamber 14 will be greater, which will also act on the impact piston 20 via the front pressure surface 26. The rearward movement of the impact piston 20, i.e. into the piston housing 12 and back again to the retracted position shown in FIG. 1, is now initiated.

[0034] In the arrangement shown in FIG. 1, the location of the annular space or spaces 15 will have an effect on the stroke length of the impact piston 20 within the piston housing 12.

[0035] If more than one annular space 15 is arranged in the impact piston 20, the stroke of the impact piston 20 can be influenced and thus adjusted through a second control device 60, which will be described in connection with FIG. 2.

[0036] According to the invention, the first control device 50 and the second control device 60 are in this case arranged in a common valve housing 70, the circuit arrangement of which is shown diagrammatically in FIG. 2 and will be described below.

[0037] As shown in connection with Figure 1, the first control device 50 may have a first control valve 52 with three ports and two valve positions. A line connection to the hydraulic feed 30 is established through port P, while a line connection to the hydraulic drain 40 and thus the tank 42 is established through port T. The first control device 50 is connected by a line to the piston housing 12 of the impact piston 20 through port S, as previously described in connection with Figure 1. A first control port 54 of the first control device 50 is connected by a line to the hydraulic feed 30, consistent with the previous description of Figure 1.

[0038] In accordance with the present invention, a second control device 60 including a second control valve 62 is also disposed within the same valve housing 70 within which the first control device 50 is disposed.

[0039] In the description shown in Fig. 2, the second control valve 62 is preferably a 4 / 3-way valve having four ports and three valve positions. Here, the outlet 64 of the second control valve 62 is connected to the second control port 56 of the first control valve 52 via a pressure control line 65. Three spaced annular spaces provided by four shoulders in a possible alternative impact piston 20 are connected to three inlets HB1, HB2 and HB3 of the second control valve 62, respectively. Through the control port 66 on the second control valve 62 side and through the actuation line 68, the machine operator can select and trigger which of the inlets HB1, HB2, HB3, and therefore which of the annular spaces 15 in the impact piston 20 are connected to the pressure control line 65 to operate the first control valve 52 according to the desired stroke length of the impact piston 20 in the piston housing 12. The arrangement of the three annular spaces in this exemplary embodiment thus establishes a longer or shorter stroke path for the impact piston 20 within the piston housing 12 .

[0040] In principle, fewer or more annular spaces 15 can also be provided in the impact piston 20, which would then require a corresponding adaptation of the second control valve 62 with a corresponding reduction or increase in the inlet.

[0041] A valve housing 70 provided for the invention, which has a box-shaped valve block 72, which can be closed on one side by a cover plate 74, is shown in FIG. 3 in various views from different sides. The cover plate 74 is only shown here in a central side view. The valve receptacle 76 and the lines or ducts forming the first control device 50 and the second control device 60 can be integrated, in particular milled, into the valve block 72. Overall, a particularly robust circuit arrangement with short line paths is thus achieved. A particularly fast actuation and changeover of stroke length can also be achieved in this way.

[0042] 3, the ports for the hydraulic feed 30 can be provided on one side of the valve housing 70, and the ports for the hydraulic drain 40 and actuation line 68 can be provided on the opposite side. A corresponding annular space connecting port HB for stroke limiting purposes can be located on the other side.

[0043] <Additional Notes> [1] 1. An impact piston device for an impact drill drive, comprising: an impact piston (20) movably mounted within a piston housing (12) so as to be reversible between a forward striking position and a rearward retracted position, the impact piston (20) having at least one forward pressure surface (26) and at least one rearward pressure surface (29), the impact piston (20) having at least one forward pressure chamber (14) and one rearward pressure chamber (16) integrally formed with the piston housing (12); a hydraulic fluid feed (30); and a hydraulic fluid drain (40); a first control (50) for alternately connecting at least the rear pressure chamber (16) for effecting the reversible movement of the impact piston (20) to the hydraulic fluid feed (30) and the hydraulic fluid drain (40); a second control device (60) capable of adjusting at least one stroke path of the impact piston (20) within the piston housing (12); said first control device (50) having an actuable first control valve (52) and said second control device (60) having an actuable second control valve (62), An impact piston device, wherein the first control valve (52) and the second control valve (62) are disposed within a common valve housing (70). [2] An impact piston device according to the above item [1], The impact piston device, characterized in that the valve housing (70) comprises a valve block (72) having fluid lines and a valve receptacle (76) formed therein, particularly milled therein. [3] An impact piston device according to the above item [2], An impact piston apparatus comprising: a cover plate (74) for closing said valve block (72) containing said fluid lines and said valve receptacle (76). [4] An impact piston device according to any one of the above [1] to [3], 1. An impact piston device, comprising: a port (P) for the hydraulic fluid feed (30), a port (T) for the hydraulic fluid drain (40), and a connection port (S) for a line connection to the piston housing (12), disposed on the valve housing (70). [5] An impact piston device according to any one of the above [1] to [4], 11. An impact piston device, characterized in that the first control valve (52) is designed as an actuable 3 / 2-way valve. [6] An impact piston device according to any one of the above [1] to [5], 1. An impact piston device, characterized in that the first control valve (52) alternately connects the piston housing (12), and in particular the rear pressure chamber (16), to the hydraulic fluid feed (30) and to the hydraulic fluid drain (40). [7] An impact piston device according to any one of the above [1] to [6], 11. An impact piston device, characterized in that the actuatable second control valve (62) is designed as a 3 / 2 way valve or as a 4 / 3 way valve. [8] An impact piston device according to any one of the above [1] to [7], An impact piston device, characterized in that an outlet (64) of the second control valve (62) is connected to a pressure control line (65) for operating the first control valve (52). [9] An impact piston device according to any one of the above [1] to [8], An impact piston device, characterized in that the inlets of the second control valves (62) are connected to the annular space (15) in the piston housing (12) by lines.

[10] An impact piston device according to any one of the above [1] to [9], An impact piston device, characterized in that a control port (66) for operating the second control valve (62) is provided on the valve housing (70).

[11] 1. An impact drill drive having at least one drill drive, An impact drill drive comprising an impact piston device (10) according to any one of the above items [1] to

[10] .

Claims

1. 1. An impact piston device for an impact drill drive, comprising: an impact piston movably mounted within a piston housing so as to be reversible between a forward striking position and a rearward retracting position, the impact piston having at least one forward pressure surface and at least one rearward pressure surface, the impact piston having at least one forward pressure chamber and a rearward pressure chamber integrally formed with the piston housing; a hydraulic fluid feed; a hydraulic fluid drain; a first control device for alternately connecting at least the rear pressure chamber for effecting the reversing movement of the impact piston to the hydraulic fluid feed and to the hydraulic fluid drain; a second control device capable of adjusting at least one stroke path of the impact piston within the piston housing; the first control device having an actuable first control valve and the second control device having an actuable second control valve; the first control valve and the second control valve are disposed within a common valve housing; the valve housing comprises a valve block having fluid lines and valve receptacles formed therein, particularly milled therein; An impact piston device including a removable cover plate for closing off the valve block containing the fluid lines and the valve receptacle.

2. 2. An impact piston device according to claim 1, An impact piston apparatus, wherein the port for the hydraulic fluid feed, the port for the hydraulic fluid drain, and a connection port for a line connection to the piston housing are located on the valve housing.

3. 2. An impact piston device according to claim 1, The impact piston apparatus, wherein the first control valve is designed as an actuatable 3 / 2 way valve.

4. 2. An impact piston device according to claim 1, An impact piston arrangement, wherein the first control valve alternately connects the piston housing, and in particular the rear pressure chamber, to the hydraulic fluid feed and to the hydraulic fluid drain.

5. 2. An impact piston device according to claim 1, An impact piston device, wherein the actuatable second control valve is designed as a 3 / 2 way valve or as a 4 / 3 way valve.

6. 2. An impact piston device according to claim 1, An impact piston device, wherein the outlet of the second control valve is connected to a pressure control line for actuating the first control valve.

7. 2. An impact piston device according to claim 1, An impact piston device, wherein the inlets of the second control valves are each connected by a line to an annular space within the piston housing.

8. 2. An impact piston device according to claim 1, A control port is provided on the valve housing for actuating the second control valve.

9. 1. An impact drill drive having at least one drill drive, An impact drill drive provided with an impact piston device according to claim 1.

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