EP0388498B1 - Hydraulic valve system for a pile driver hammer - Google Patents

Description

The invention relates to a hydraulic valve combination, in particular for controlling a piston-cylinder unit for free-fall hammers with a control valve which switches a hydraulic actuating element which actuates the main valve, the actuating element and the main valve being designed as a common axially displaceable control slide.

Such a hydraulic valve combination is known from GB-A-20 69 034. The control housing is arranged on one end of the piston-cylinder unit and closes it. The axially displaceable control slide has the same diameter as the piston of the piston-cylinder unit and interacts with corresponding bores in the pressure medium cylinder so that the pressure medium supply and the pressure medium return are switched accordingly.

The control slide is designed at one end as a piston which is located in a cylindrical space of the control housing and is acted upon with pressure medium via bores in such a way that it moves the control slide axially.

The pressure medium supply lines for actuating the control piston can be switched electrically by means of a solenoid valve.

A disadvantage of the known prior art is that the known hydraulic valve combination has to be specially adapted to the respective cylinder diameter, because the spool moves in the cylinder. As a result, it is not possible to achieve quantities that reduce the manufacturing effort.

In addition, the control slide has a disadvantageously high mass, which affects the quick switchability of the valve.

In addition, the flow of force when the impact mass is raised is passed through the control valve housing, so that the valve housing must be dimensioned accordingly strong. Since connecting elements and seals of the control valve are in the power flow, the tightness of the control valve is endangered by rough operating conditions.

Finally, the maintenance effort is disadvantageously increased in that the entire cylinder unit has to be dismantled in order to disassemble the control valve.

Due to the progressive improvements in computer technology, both in terms of performance and the now manageable sizes and components, it is becoming more and more interesting to let piling equipment work completely computer-controlled in an automatic adaptation to the given operating conditions and for control and later Evaluation to store the operating data electronically and / or to print them out using a printer.

While the transmission of the signals and their processing in the computer for control commands that initiate the control process take place very quickly go, the execution of the control processes is very slow in comparison. The result is that the drop weight continues to move for an unintentionally long time in the direction no longer desired after the control process has been initiated. In the upper reversal point of the drop weight, there are considerable overflow paths, which also differ depending on the upward speed, which requires constant control and adjustment processes. Likewise, the pressure medium flow must be reversed long before the impact in order to reverse the falling weight after the ram impact, ie if the falling weight is still relatively far above the impact point in the downward movement. Depending on whether the falling weight falls very quickly from a high height or slowly from a very low height, this requires, for example, adaptation measures with regard to the correct changeover time. It can also lead to a restriction of the minimum stroke, because this already falls into the necessary pilot control route for the high falling speeds at the high strokes.

The larger the devices, the more significant these negative phenomena become. The larger the devices to be controlled, the greater are the actuating forces required for the actuators performing the control process. The actuators grow with the size of the device because more pressure medium quantities have to be left through the control valves at a given flow rate, which inevitably requires larger cross sections and more travel and thus a more voluminous design. In any case, with increasing Unit size to move larger masses on longer paths against larger actuating forces.

In some cases it is possible to select several smaller actuators instead of larger and larger ones to carry out the control processes. However, this has the disadvantage that the number of potential malfunctions and failures is multiplied and the device becomes more susceptible, which has a particularly disadvantageous effect on the piling equipment which is highly stressed by vibrations.

Another problem with the control of pile drivers is that it has so far not been possible to design a controller that controls both the device in such a way that it can alternatively work with an accelerated but also with an unaccelerated drop weight, i.e. in free fall. That is, the piston surface of the pressure medium piston for lifting the falling weight is accelerated downward in the first case by pressurized pressure medium or in the other case is only acted upon by pressureless pressure medium, with no accelerating force being generated.

For this reason, devices with accelerated and unaccelerated falling weight coexist and are used differently according to their application advantages.

It would be of considerable advantage if both application advantages could be achieved with just one device, because only one device then needs to be kept available for the entire range of applications.

The object of the invention is to provide a hydraulic valve combination which operates in a particularly delay-free manner and which, moreover, is easy to maintain, works reliably, can be used for different circuits and reduces the number of parts. In particular, it should offer the possibility of operating the pile driver with free-falling as well as with accelerated impact mass.

To achieve the object, the hydraulic valve combination has the features of claim 1.

The design according to the invention advantageously keeps the moving masses low, so that the hydraulic valve combination switches particularly quickly.

The fact that the control slide is designed as a sleeve and is arranged displaceably on a shaft which has a fixed connection to a flange plate closing the control housing, makes maintenance of the hydraulic valve combination easier.

In this embodiment according to the invention, the rapid interchangeability required for large devices is given in that the control slide guided and fastened on the central shaft of a flange plate can be easily removed together with this plate as a complete unit, so that downtimes can be kept to a minimum .

In addition, in this version the control slide is not in any phase of the lifting and Falling movement of the falling body or the working piston with these parts in contact, so that especially the rebound forces acting violently during the impact phase cannot act on the falling weight.

Another important design feature is that the entire control slide unit, including the control valve, is designed as a complete installation element and can therefore be tested for function beforehand by installing it in a small test housing without great effort.

The different circuit options are particularly advantageous, so that the impact mass can be operated with little effort both in free fall and with accelerated fall.

Advantageous embodiments of the invention are described in subclaims 2 to 14.

• Fig. 1 zeigt einen schematischen Längsschnitt durch ein Rammgerät mit Steuerungsvorrichtung,
• Fig. 2 zeigt einen vergrößerten Längsschnitt durch die Steuerungsvorrichtung in einer abgewandelten Form und in einer anderen Schaltstellung,
• Fig. 3 zeigt die Steuerungsvorrichtung gemäß Fig. 2 mit einem abgewandelten Steuerschieber und
• Fig. 4 zeigt die Steuerungsvorrichtung gemäß Fig. 3 in anderer Schaltstellung.

Exemplary embodiments are explained below with reference to drawings.

• 1 shows a schematic longitudinal section through a pile driver with control device,
• 2 shows an enlarged longitudinal section through the control device in a modified form and in another switching position,
• FIG. 3 shows the control device according to FIG. 2 with a modified control slide and
• FIG. 4 shows the control device according to FIG. 3 in a different switching position.

Circumferential edges have not been shown in all the figures in order to keep the figures manageable.

In Fig. 1, the drop weight 1, which is only partially shown, is connected via a piston rod 2 to a piston 4 located in a piston-cylinder unit 3. To lift the falling weight 1, pressure medium is guided under the piston 4 into the space 5. The pressure medium is introduced by the pump 6 via the line 7, the connecting line 8 of the device in an annular channel 9 and the line 10 into the annular space 11, which surrounds the pressure medium cylinder 3, and passed through connection bores 12 into the space 5.

The space 5 is thus in constant communication with the pump 6.

The space 13 above the working piston 4 is connected to the pressure medium container 20 via the line 14 and the connecting bores 15 in the control slide 16, an annular channel 17 and the device connecting line 18 and the return line 19.

In this switching position, the control slide 16 bears firmly against the stop 21. It closes the annular channel 9 with its circumferential surface and thus does not allow pressure medium to enter the space 13. The control slide 16 is guided on a central shaft 22 which is connected to a flange plate.

The design of the control slide 16 and the shaft 22 form two separate annular spaces 23 and 24, which are connected via lines 25 and 26 to an electro-magnetic valve 27.

The electro-magnetic valve 27 connects via these lines 25 and 26, depending on its switching position, the annular spaces 23 and 24 via lines 28 and 29 either via the pressure medium supply lines 10, 9, 8, 7 with the pump 6 or via the Pressure medium return lines 17, 18 and 19 with the pressure medium container 20. The lines 25 and 26 and the lines 28 and 29 are only short due to the overall design and their cross section in relation to the small annular spaces 23 and 24 to be filled or emptied Large cross-section so that the filling or emptying quantities flow without significant back pressure losses and time delays and can move the control slide 16 quickly into the desired position.

The control slide 16 is designed as a thin, low-mass pipe section with a concentrically placed ring, the diameter of which results from the cross section of many connecting bores 15 arranged on the circumference, which is required for the flow. Due to this low-mass design, the control slide 16 can be accelerated quickly, that is, switched quickly, by means of already comparatively low actuating forces in the annular space 23 and 24.

In Figure 2, the control slide 16 is in its second switching position. It rests against stop 30. In this switching position, the space 13 is connected to the pump 6 via the line 14, the ring channel 9, the connecting line 8 and the line 7. At the same time, the pressure medium continues to be supplied to the space 5 under the working piston 4 via the line 10, as described under FIG. 1.

In contrast to FIG. 1, the additional line 32 with ring channel 33 and the additional line 34 are also in connection with ring channel 33 in FIG. 2 in the control housing 31. The line 34 is closed by the screw plug 36, so that no leakage oil can escape to the outside can. In the control housing 31, a screw plug 37 with a sealing cone 38 is also provided, with which the line 28 can be shut off from the solenoid valve 27.

With this embodiment, the control housing 31 can be used universally as described below in FIG. 3.

In Fig. 3, a control slide 16a is installed in the control housing 31 described in Fig. 2, which has an annular recess on its outer circumference. In addition, instead of the screw plug 36, a line 40 is connected to the line 34, which leads to the line 7 and connects to the pump 6.

The locking screw 36 closes the connecting line 8 here. The control slide 16a is located at the stop 21 and thus assumes the switching position in this figure as in FIG Falling weight 1 pressure medium from the pump 6 via the line 7 is now passed into the connecting line 40, the annular recess 39, the line 10, the annular space 11 and the connecting bores 12 into the space 5.

The space 13 above the working piston 4 is connected via the line 14, the connection bores 15 in the control slide 16a and via the connecting line 18 to the return line 19 and thus to the pressure medium discharge with the pressure medium container 20.

The function of the embodiment modified compared to FIG. 1 thus still corresponds to the function described in FIG. 1.

The line 28 is closed by the sealing cone 38 of the screw plug 37. The electromagnetic solenoid valve 27 is now connected via line 32 to the annular space 39 and thus continuously to the pump 6.

4, the control slide 16a is in its second switching position corresponding to FIG. 2. In contrast to the embodiment in FIG. 2, the control slide 16a now no longer connects the space 13 above the working piston 4 to the pump 6 because the line 8 passes through the valve 50 to the pump is closed, but rooms 5 and 13 are only connected via line 10, as in FIG. 2. As a result, the pressure medium which is displaced from the chamber 5 by the working piston 4 when the drop weight 1 falls freely is guided into the chamber 13 without the pump 6 additionally feeding in pressure medium. The In this switching phase, pump 6 delivers pressure medium via line 41 into memory 42.

Depending on the design of the free fall hammer, whether e.g. to receive the pressure medium volume displaced from the space 5 into the space 13 above the working piston 4, the piston rod 2 is passed through the space 13 and its cover 43 in the same diameter or with a slightly larger or slightly smaller diameter, corresponds to that displaced from the space 5 Quantity of pressure medium exactly the amount taken up in space 13 or there is an excess that has to be drained off to the tank or collected in a store, or there is a shortage, for example each must be supplemented from memory. The latter applies if the piston rod 2 is not continued above the working piston 4, so that there is a considerable volume unevenness between the rooms 5 and 13. The volume compensation required in each case can be created by switching the valve 50 accordingly, so that missing or excess pressure medium can be conveyed out of or into the reservoir via line 40.

In FIG. 4, instead of the screw plug 37, an electro-magnetic valve 44 is alternatively provided, which closes the line 28, and which opens if necessary to connect the line 28 via the line 45 to the valve 27.

In addition, instead of the screw plug 36 shown in FIG. 3, an electro-magnetic valve 50 has been alternatively arranged, which the line 8th closes and continues to connect line 34 to pump 6 via lines 40 and 7 as in FIG. 3.

If both valves 44 and 50 are coupled to each other in their actuation, the operation can be changed from the accelerated to the unaccelerated falling weight mode, that is to the free fall mode, and vice versa during operation.

Of course, instead of the locking screws 36 and 37 as well as instead of the valves 44 and 50, manually or hydraulically operated valves can be arranged. 1 Drop weight 31 Timing case 2nd Piston rod 32 management 3rd Pressure cylinder 33 Ring channel 4th piston 34 management 5 room 35 Flange plate 6 pump 36 Screw 7 management 37 Screw 8th Connecting cable 38 Sealing cone 9 Ring channel 39 Recess 10th management 40 management 11 Annulus 41 management 12th Connecting hole 42 Storage 13 room 43 cover 14 management 44 Valve 15 Connecting holes 45 management 16 Spool 46 first annulus 17th Ring channel 47 second annulus 18th Device connection line 48 Active connection 19th Return line 49 Sensors 20th Pressure medium container 50 Valve 21 attack 22 shaft 23 Annulus 24th Annulus 25th management 26 management 27th Solenoid valve 28 management 29 management 30th attack

Claims (14)

1. Hydraulic valve combination, in particular for activating a piston/cylinder unit (3, 4) for drop pile hammers, having a control valve (27), which controls a hydraulic actuating element (23, 24), which actuates the main valve (9, 17), the actuating element and the main valve taking the form of a common, axially displaceable slide valve (16), characterized in that the slide valve (16) is disposed in a control housing (31) and takes the form of a sleeve, whose inside is provided with function faces of the hydraulic actuating element and on whose outer surface are disposed function faces of the main valve, with the slide valve (16) being disposed displaceably on a shaft, which has bores (25, 26) for hydraulic actuation of the slide valve (16), and the slide valve (16) being disposed so as to cooperate with a control housing (31), which externally and concentrically surrounds it, in such a way as to operate annular channels (9, 17) with connection lines (8, 18) for supplying or returning pressure medium and connection lines (10, 14) leading to the piston-cylinder unit.
2. Hydraulic valve combination according to claim 1, characterized in that the slide valve (16) is disposed so as to divide an annular chamber formed by the shaft (22) and the control housing (31) into a first (46) and a second annular chamber (47) and has connection bores (15) which connect the annular chambers.
3. Hydraulic valve combination according to claim 1 or 2, characterized in that the shaft (22) is permanently connected to a flange plate (35) which closes the control housing (31).
4. Hydraulic valve combination according to claim 1, 2 or 3, characterized in that the control valve (27) is disposed on the flange plate (35).
5. Hydraulic valve combination according to claim 1, 2, 3 or 4, characterized in that the hydraulic valve combination is permanently connected to a piston/cylinder unit (3), in particular that of a pile hammer.
6. Hydraulic valve combination according to claim 1, 2, 3, 4 or 5, characterized in that the control housing (31) has at least one controllable return line (19) to the first annular chamber (46) and at least one controllable supply line (7 or 40) to the second annular chamber, as well as at least one permanently open line (14) and at least one controllable line (10) to the piston/cylinder unit (3).
7. Hydraulic valve combination according to claim 1, 2, 3, 4, 5 or 6, characterized in that the flange plate (35) has lines (25, 26) to annular chambers (23, 24) between shaft (22) and slide valve (16) as well as lines (29, 28) to the return line (19) and to the controllable line (10).
8. Hydraulic valve combination according to claim 1, 2, 3, 4, 5, 6 or 7, characterized in that the control valve (27) is disposed on the flange plate (35) so as to control the lines (25, 26, 28, 29).
9. Hydraulic valve combination according to claim 1, 2, 3, 4, 5, 6, 7 or 8, characterized in that an additional annular channel (33) is provided, which is connected to a line (34) and to a line (32).
10. Hydraulic valve combination according to claim 9, characterized in that the line (34) of the annular channel (33) is connectable to the supply line (7) and line (32) of the annular channel (33) is connectable to line (28) and the controllable line (10).
11. Hydraulic valve combination according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, characterized in that the control valve (27) has an operational connection (48) to sensors (49) which detect the position of the drop weight (1).
12. Hydraulic valve combination according to claim 9, 10 or 11, characterized in that provided between the supply line (7) and lines (8, 34) is an operating valve (50) which selectively connects the line (8) or line (34) to the supply line (7).
13. Hydraulic valve combination according to claim 9, 10, 11 or 12, characterized in that disposed between line (28) and line (32) is a valve (44) which selectively connects said lines.
14. Hydraulic valve combination according to claim 12 or 13, characterized in that the operating valve (50) and valve (44) are coupled to one another.

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