EP1632637B1 - Soil working tool and method for introducing a working element into the soil - Google Patents

Abstract

The implement has a vibration generator with a vibrating piston (42) which is mounted in linearly displaceable manner in a casing so as to be spaced from a working unit (5). The piston is driven in oscillating manner for generating vibrations. The vibrations can be transmitted to the working unit through the casing. The vibrating piston has two piston surfaces, where one surface is subject to an alternating pressure. An independent claim is also included for a method for introducing a working unit into the ground.

Description

The invention relates to a cultivator for introducing a working element in the ground using vibrations, with a vibration generator, which is designed for generating and transmitting vibrations to the working element. The invention further relates to a method for introducing a working element into the ground, in which vibrations are generated and transmitted to the working element during its introduction into the ground.

The WO 2004/009298 A describes a drill with a working piston inside a cylinder chamber. The working piston is vibrated by alternately applying a pressure above and below the piston, with the piston reciprocating in a bore. The cylinder chamber has an inlet portion for introducing the pressurized fluid into the bore above a first surface of the working piston and an outlet portion for expelling the pressurized fluid from the bore below the second surface of the working piston.

For driving sheet piles or piles into the ground, so-called vertical vibrators with vibrating cells are known. Such a vertical vibrator is for example from the EP 0 824 971 B1 out. The vibrating cell described herein has paired driven rotating imbalances that are synchronized by gears, so that the resulting inertial forces occur substantially only in one direction of action. The laterally acting centrifugal forces should compensate each other by the special synchronization of the gears.

U.S.-A-4,155,287 discloses a hydraulically operated impact device with a piston reciprocated in a cylinder. The hydraulic energy for this is generated by a hydraulic pressure fluid in the cylinder, wherein the pressure change is controlled by a valve. The valve is actuated between the switching positions by means of triggering openings, which are opened and closed by means of a rod with recesses. The rod connects the piston with a striking tool, such as a ram. The movement of the piston has a working and a Leerhub.

Prerequisite for this are tight manufacturing tolerances in the teeth. In addition, the waves carrying the imbalances must be dimensioned correspondingly large to minimize deflection, resulting in a corresponding size of such a Rüttelzelle. Due to the heavy mechanical load, the gears must be manufactured with high strength and surface quality. Furthermore, the life of the bearings is limited by the strong dynamic load.

Another problem with these known Rüttelzellen is that with large aggregates because of the inertia they can be ramped up from standstill only slowly up to the rated speed. As a rule, a resonance frequency of the first or higher order must be passed through. There is a risk of increased amplitude, which can lead to damage. To avoid this, the imbalances in larger units are usually arranged swing out so that they are switched only at the rated speed reached. For this purpose, however, a complex additional device is necessary, which further increases the size and the cost of the overall device.

From the DE 102 37 407 A1 is a percussion hammer with a hydraulically driven percussion piston known. The percussion piston is mounted linearly displaceable in a piston housing, in which open control lines for supply and discharge of hydraulic fluid. The hydraulic fluid is supplied and removed in a controlled manner via these lines, so that the percussion piston is set in an oscillating motion. The percussion piston points with its impact surface out of the piston housing. Due to the oscillating movement of the Impact pistons may be impacted to a back end of a drill string via the impact surface so that percussion drilling can be performed.

In this mechanical impact generation creates a significant noise emission. The blows pass through the drill string in the form of a sound wave, with the drill pipe located in the open air acting as a resonator that is virtually unbeatable and radiates a large part of the sound to the environment. Such impact drilling must therefore not be used on certain construction sites with strict noise control regulations. In addition, the mechanical impact generation leads to a significant load on all components, especially the bearings, guides and seals. Their lifetime is therefore also considerably limited.

The invention has for its object to provide a harrow and a method for introducing a working element in the ground, in which vibrations effectively and as gently as possible be transferred to the working element.

The object is achieved by a harrow with the features of claim 1 and by a method having the features of claim 12. Preferred embodiments of the invention are indicated in the dependent claims.

The soil cultivation device according to the invention is characterized in that the vibration generator has at least one oscillating piston which is mounted in a housing linearly displaceable and spaced from the working element, the oscillating piston is driven to oscillate in order to generate vibrations and that the vibrations can be transmitted to the working element via the housing.

A basic idea of the invention can be seen in arranging the oscillatingly driven piston in a closed housing. The vibration transmission takes place indirectly via the housing. Unlike a hydraulic percussion hammer creates no impact contact between metal parts, so that in the invention significantly less noise is given. The inertia of the mass to be accelerated within the vibrator is inherently very low, so that a possible resonance range can be traversed comparatively very quickly. There are also virtually no dead masses that need to be accelerated. Due to the principle, no lateral mass forces can occur. Rotatable components and vulnerable seals between housing and piston can be omitted. The components used are simple and robust, so that they are very well suited for site conditions. The device can be made very compact overall.

A particularly high vibration energy can be generated according to the invention in that the oscillating piston is hydraulically driven. A hydraulic pressure generator is located on most civil engineering machines, which are used for earth or rock processing.

According to the invention, it is particularly preferred that the oscillating piston has a first piston surface and a second piston surface, of which at least one with changing Pressure is applied. As a result, an almost arbitrary oscillating movement of the oscillating piston can be set, which preferably has a sinusoidal, harmonic path-time profile. The pressurization can be effected by an equal high pressure, which is alternately exerted on the opposite piston surfaces. Alternatively, a constant pressure can be exerted on a piston surface, while an up-and-down pressure is exerted on the opposite piston surface in order to generate the oscillating movement of the oscillating piston.

In principle, the size of the two piston surfaces can be identical. Depending on the adjustable pressure ratios, however, a different area ratio of the two piston surfaces, approximately 2: 1 can be provided. This allows an even freer adjustment of the oscillation behavior of the oscillating piston.

A simple and robust control according to the invention can take place in that the oscillating piston is designed as a primary control piston, with which the alternating pressurization is controllable. The control is done so to speak "own excited". The oscillating piston is formed with control edges, which form the function of a first control piston. Depending on the position of the oscillating piston can thus be carried out an automatic reversal of the pressurization. Such control of an oscillating piston is already known in principle from the operation of the percussion piston in the hydraulic impact hammers of the prior art.

An embodiment of the invention is given by the fact that a control device is provided, with which the movement of the oscillating piston is controllable. By such a control device, which may have, for example, an outer control valve, the control of the oscillating piston is, so to speak, "foreign-excited". Preferably, the control device comprises an electronic control unit for controlling or regulating the supply and discharge of the pressurized fluid in order to set a desired oscillation behavior of the oscillating piston. The control device can also have a secondary control piston, by which a pressure fluid is switched alternately.

The working element may be according to the invention, a sheet pile or a pile, which is rammed directly into the ground. In this case, it is according to the invention that the housing of the vibration generator is fastened to a tensioning device for holding the working element. The generated vibration can be transmitted via the housing and the clamping device directly to the working element.

Furthermore, it is provided according to the invention that the housing of the vibrator is arranged on a drive housing of a drill drive and that the working element is designed as a drilling tool. According to the invention, a particularly gentle superimposition of the rotating drilling movement with the oscillation movement directed in the drilling direction can be achieved. This allows a high rate of drilling with a special great protection of the drilling tool and in particular the drill drive with its bearings.

According to a further preferred embodiment of the invention it is provided that the processing element has a carriage for receiving the working element, which is movably mounted on a guide. For example, by means of a cable drive or a rack drive, an additional force can be exerted on the working element via the carriage in order to drive this into the ground. Depending on the soil conditions, the force for driving the working element into the ground can be applied solely by the oscillatory movements in combination with the weight of the working element and the associated carriage. The carriage may be guided on a mast or broker, which is attached, for example, to a superstructure of a construction vehicle.

A particularly low-vibration arrangement is inventively achieved in that the working element is mounted elastically relative to the carriage. In this case, an elastic bearing may be provided on the clamping device or the drill drive. Preferably, the working element is suspended elastically on the carriage via the housing of the vibration generator. This ensures that the vibrations are transmitted largely undisturbed to the working element, while the carriage and the associated parts of the processing device remain free of vibration as possible.

For a particularly good oscillation movement of the oscillating piston, it is inventively provided that the oscillating piston has a through bore. The through bore allows quick venting of the cylinder chambers.

The inventive method is characterized in that the vibrations with at least one oscillating piston be produced, which is linearly displaceable in a housing and spaced from the working element, that the oscillating piston is driven to oscillate oscillating and that the vibrations are transmitted through the housing to the working element. This method can be carried out in particular by the previously described soil cultivation device according to the invention, with the advantages described above resulting. Underground is not only the soil but also rocks, for example, by rock walls to understand. The vibration generation can be generated with one or more oscillating piston, which are connected in parallel.

This method is inventively further developed in that a drilling tool is used as the working element, which is driven in rotation, and that the vibrations are transmitted in the drilling direction to the drilling tool. Due to the oscillation of the drill string according to the invention, the frictional forces in the interface with the surrounding soil can be reduced. This leads to a considerably faster drilling progress. The use of the method according to the invention is particularly advantageous when overlay drilling light overlay floors where the impact of a conventional hydraulic chamber is hardly useful.

Fig. 1

ein Beispiel eines erfindungsgemäßen Bodenbearbeitungsgerätes in einer Seitenansicht;

Fig. 2

eine Querschnittsansicht eines Bohrantriebes mit Schwingungserzeuger;

Fig. 3

eine Querschnittsansicht eines Bohrantriebes mit einem abgeänderten Schwingungserzeuger;

Fig. 4

eine Darstellung der Druckverläufe über die Zeit;

Fig. 5

eine Querschnittsansicht eines Schwingungserzeugers mit Spanneinrichtung; und

Fig. 6

eine schematische Darstellung einer elastischen Aufhängung an einem Schlitten.

The invention will be further described by means of preferred embodiments, which are schematically illustrated in the drawings. In the drawings show:

Fig. 1

an example of a tillage implement according to the invention in a side view;

Fig. 2

a cross-sectional view of a drilling drive with vibrator;

Fig. 3

a cross-sectional view of a drill drive with a modified vibration generator;

Fig. 4

a representation of the pressure curves over time;

Fig. 5

a cross-sectional view of a vibrator with tensioning device; and

Fig. 6

a schematic representation of an elastic suspension on a carriage.

In the soil cultivation device 10 according to FIG. 1, a tracked vehicle 12 with an operating unit 14 is provided. Via a lever mechanism 16, a mast 18 can be brought into a desired position, in which this can be placed with a provided at the lower end clamping and release device 17 on the soil to be processed. The mast 18 has a linear guide 19, along which a carriage 20 is movable via a drive, not shown. On the carriage 20, a drill drive 60 is fixed, which can drive a designed as a drill pipe work element 5 rotating. On the side facing away from the working element 5 side of the drill drive 60, a vibration generator 40 is mounted, with which generates vibrations according to the invention and can be transmitted during drilling over the drill drive 60 to the working element 5.

In Fig. 2 the drill drive 60 is shown with the vibration generator 40 in an enlarged view. About its drive housing 62 of the drill drive 60 is welded to the carriage 20, which is mounted linearly displaceable on the guide 19 of the mast 18. Via a gear motor not shown in detail 64 with hydraulic connections 66, the working element 5 designed as a drill rod is rotationally driven about the drilling axis 7 via a gear transmission.

At the side facing away from the working element 5 side of the drill drive 60, a housing 44 of the vibrator 40 is flanged to the drive housing 62. The housing 44 consists of a base housing 45, which is closed by a cover 46. The housing 44 encloses a cylinder space in which a oscillating piston 42 is mounted linearly displaceable along a piston axis 43. For a good vibration transmission, the piston axis 43 is aligned with the drilling axis 7 of the working element 5 to be driven.

The oscillating piston 42 has two cylindrical shoulders which, at their outer sides facing the free ends, form a first piston surface 48 and a second piston surface 49, respectively. The two piston surfaces 48, 49 in each case close off an adjacent pressure chamber, into which a pressure fluid can be alternately supplied and removed via pressure lines in order to set the oscillating piston 42 into a desired oscillating or reversing linear movement. To generate the alternating pressurization, a control device 30 is provided with an additional control piston 32 in the illustrated embodiment, which with the leading into the cylinder chamber control lines and the oscillating piston 42 provided control edges a own excited Pressure change causes. Such a self-excited control of an oscillating piston is already known in principle from the prior art in hydraulic hammers, so that this control does not need to be described in detail.

For mutual venting of the two end cylinder chambers in the housing 44 of the oscillating piston 42 is provided with a through bore 47. In addition, the basically closed housing 44 is vented through a vent hole 34 to the closed drive housing 62 out.

FIG. 3 shows an alternate form of the vibrator 40 of FIG. 2. While the first piston surface 48 and the second piston surface were the same in the vibrator 40 of FIG. 2, in the embodiment of FIG. 3, the second piston surface 49 is twice as large In addition, only two pressure lines 1 and 2 open into the housing 44. The control device may be electrically or hydraulically actuated valves, which are not shown in greater detail. As a result, in contrast to the embodiment of FIG. 2, a third-excited, ie independent of the position of the oscillating piston 42 control cause. Incidentally, the embodiment of Fig. 3 is formed according to the embodiment of Fig. 2. The embodiment in FIG. 3 can also be set in self-excited oscillations with the control shown in FIG.

In the diagram of Fig. 4, the pressure profile at the pressure ports 1 and 2 is shown schematically. Thus, a constant pressure can be applied to the pressure port 1, while at the pressure port 2 a changing over time Pressure is applied, so that the desired oscillating movement of the oscillating piston 42 is generated. In response to the oscillation of the oscillating piston 42, a vibration of the housing 44 is effected, which transmits to the drive housing 62 via the annular, coaxial to the piston axis contact surface. About the drive housing 62 of the drill drive 60, the vibrations are transmitted to the working element 5, so a rotational movement of a drill string with axial vibrations can be superimposed.

In the cultivator 10 according to FIG. 5, a vibration generator 40 is used, as has already been described in the embodiment of FIG. 2. In the embodiment shown in FIG. 5, the vibration generator 40 is rigidly connected to a tensioning device 50 via a flange element 22. The tensioning device 50 is designed to hold a sheet pile screed. Attached to a vertically movable carriage can be rammed or shaken by means of the processing device 10 shown a sheet pile wall in the ground.

In Fig. 6, a preferred suspension of the vibrator 40 on the carriage 20 is shown. On the carriage 20, a housing 24 is fixed, in which the vibration generator 40 is suspended elastically via rubber bearings 26. The rubber bearings 26 are formed with a metallic inner and a metallic outer attachment. Between these two metallic, preferably annular fasteners is an elastic rubber compound, which avoids excessive transmission of vibrations from the vibrator 40 to the housing 24 and the carriage 20 connected thereto. This ensures that the majority of the vibration energy can be transferred to the work element 5 to be introduced into the soil.

Claims (13)

1. Ground working implement for introducing a working element (5) into the ground making use of vibrations and having a vibration generator (40) constructed for generating and transmitting vibrations to the working element (5), wherein the vibration generator (40) has at least one vibrating piston (42), which is mounted in linearly displaceable manner in a casing (44) and is driven in oscillating manner for generating vibrations,
   characterized in that

   - the vibration piston (42) is mounted spaced from the working element (5) with no percussive contact, and

   - the working element (5) is held at the casing (44), and the vibrations are indirectly transmittable via the casing (44) to the working element (5).
2. Ground working implement according to claim 1,
   characterized in that
   the vibrating piston (42) is hydraulically driven.
3. Ground working implement according to claim 1 or 2,
   characterized in that
   the vibrating piston (42) has a first piston surface (46) and a second piston surface (48), whereof at least one is subject to an alternating pressure.
4. Ground working implement according to claim 3,
   characterized in that
   the piston surfaces (46, 48) have a different size.
5. Ground working implement according to one of the claims 1 to 4,
   characterized in that
   the vibrating piston (42) is constructed as a control piston with which the alternating pressurization is controllable.
6. Ground working implement according to one of the claims 1 to 4.
   characterized in that
   a control device is provided for controlling the movement of the vibrating piston (42).
7. Ground working implement according to one of the claims 1 to 6,
   characterized in that
   the casing (44) of the vibration generator (40) is located on a clamping device (50) for retaining the working element (5).
8. Ground working implement according to one of the claims 1 to 6,
   characterized in that
   the casing (44) of the vibration generator (40) is located on a driving casing (62) of a boring drive (60) and that the working element (5) is constructed as a boring tool.
9. Ground working implement according to one of the claims 1 to 8,
   characterized in that
   a slide (20) is provided for receiving the working element (5) and is displaceably mounted on a guide (19).
10. Ground working implement according to claim 9,
    characterized in that
    the working element (5) is elastically mounted relative to the slide (20).
11. Ground working implement according to one of the claims 1 to 10,
    characterized in that
    the vibrating piston (42) has a through bore (47).
12. Method for introducing a working element (5) into the ground, particularly using a ground working implement (10) according to one of the claims 1 to 11, in which vibrations are generated and transmitted to the working element (5) during the introduction thereof into the ground,
    wherein the vibrations are generated with at least one vibrating piston (42), which is linearly displaceable in a casing (44), and which is driven in oscillating manner for generating vibrations,
    characterized in that

    - the vibrating piston (42) is mounted and driven spaced from the working element (5) with no percussive contact, and

    - the working element (5) is held at the casing (44), wherein the vibrations are indirectly transmitted via the casing (44) to the working element (5).
13. Method according to claim 12,
    characterized in that
    the working element (5) is constituted by a boring tool driven in rotary manner and that the vibrations are transmitted in the boring direction to the boring tool.

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