EP1893819B1 - Vibrating plate with individually adjustable vibration generators - Google Patents

Description

The invention relates to a vibrating plate according to the preamble of patent claim 1.

Vibration plates are known and consist, in principle, of a lower mass having a ground contact plate and an upper mass resiliently coupled to the lower mass and having a drive (for example a combustion or electric motor). The drive drives a belonging to the lower mass, the ground contact plate acting on vibration exciter device.

As a vibration exciter device, a so-called single-shaft exciter or towing oscillator is known, in which the drive rotatably drives an imbalance shaft carrying an imbalance mass. The imbalance shaft tears at its rotation, the ground contact plate upwards and forwards to achieve a forward movement. Thereafter, the ground contact plate is pressed by the action of the imbalance shaft down and strikes the soil to be compacted.

For larger vibration plates, the vibration exciter device has two or three mechanically or positively coupled unbalanced shafts. In the case of the so-called two-wave exciter, two imbalance shafts, each carrying an imbalance mass, are positively coupled and arranged to rotate in opposite directions. The phase angle of the imbalance shafts to each other can be adjusted mechanically via a link device or a differential gear. As drives for the adjustment hydraulic cylinders, Bowden cables or spindles are known. By adjusting the phase position of the unbalanced shafts to each other, the direction of a resulting force vector can be changed, which leads to a change in the propulsive behavior. In particular, a forward and a reverse drive of the vibrating plate can be achieved in this way.

In a further development, the imbalance mass is divided on one of the imbalance shafts into two or more part-imbalance masses which are adjustable relative to one another. If the partial imbalance masses on the imbalance shaft are adjusted asymmetrically to each other, a yaw moment can be reversed generate the vertical axis of the vibrator, whereby the vibrating plate can be steered. In a symmetrical adjustment, in particular, if fixed unbalance masses are fixedly mounted on the imbalance shaft in question and other partial imbalance masses are relatively movable, the resulting imbalance effect can be adjusted, which allows adjustment of the resulting imbalance forces.

Due to the strong imbalance, the forces on the adjusting drives for adjusting the phase position of the imbalance shafts to each other and the phase position of the various imbalance masses on an imbalance shaft are high. The adjustment mechanism is exposed to high alternating forces, which affects its service life.

Usually, the imbalance shafts are arranged parallel to each other in known vibration exciter devices. With modern vibration plates, it is thus possible to achieve a forward and a reverse drive and to turn the vibrating plate on the spot or to go around a curve. In some applications, however, the user desires a transverse movement of the vibrating plate, e.g. B. to drive behind lateral projections. During soil compaction of laterally inclined surfaces, the vibrating plate often drifts down obliquely, requiring the operator to tilt the vibrating plate for compensation. However, the bottom is compacted at the top and bottom edge only by a corner of the ground contact plate, resulting in insufficient compaction results.

In these applications, it would be helpful if the vibrating plate could perform a transverse movement. In order to achieve such a transverse movement, however, a corresponding force effect in the transverse direction would have to be achieved by the vibration exciter, which is possible only by obliquely or angularly arranged unbalanced shafts. The angular arrangement of unbalanced shafts in known vibration exciter devices and their mechanical coupling to the common drive would require a considerable amount of gearbox and accordingly high costs and weight.

From the DE 100 53 446 A1 is a vibrating plate with an upper mass and a bottom contact plate having lower mass known. The ground contact plate is acted upon by a vibration exciter device with two vibration exciters. Each of the vibration exciters consists of two parallel, mutually positively rotatably coupled and counter-rotating shafts, each carrying an imbalance and are arranged mutually adjustable in their relative phase position.

The invention has for its object to provide a vibrating plate, in which the mechanical complexity for the drive of the unbalanced shafts in the vibration exciter device can be reduced.

According to the invention the object is achieved by a vibration plate according to claim 1. Advantageous developments of the invention are specified in the dependent claims.

A vibration plate according to the invention has an upper mass comprising a drive, a lower mass having at least one ground contact plate and a vibration exciter device acting on the ground contact plate. The vibration exciter device has at least two individual exciters, each comprising at least one imbalance shaft carrying an imbalance mass. The individual exciters are according to the invention individually controllable with respect to the speed and / or the phase angle of the respective unbalanced shaft.

Thus, small units in the form of individual exciters are provided according to the invention, which in the simplest case have only a single unbalance shaft. The rotational speed and the phase angle of this imbalance shaft can be controlled individually, ie independently of the rotational speed or the phase position of further unbalanced shafts. The entire vibration exciter device, however, has at least two of these individually controllable individual exciter.

The phase position of the imbalance shaft relates to their relative position in relation to the one or more, with it cooperating imbalance waves. If one of the imbalance shafts defined as a reference system, the other unbalanced shaft or the other unbalanced shafts can either rotate with the same phase or be rotated by a certain phase angle. The phase angle of each of the unbalanced shafts should be defined in terms of a unified frame of reference.

In a particularly advantageous embodiment of the invention, each of the individual exciters on the respective imbalance shaft rotationally driving hydraulic motor or electric motor and the position of the imbalance shaft in at least one position detecting position sensor. This can on the one hand Each of the unbalance shafts are individually driven by their associated hydraulic motor (electric motor), while on the other hand via the position sensor, the actual position of the imbalance shaft is regularly or constantly monitored. The position sensor should detect the position of the imbalance shaft at least in one position, ie during one revolution of the imbalance shaft once, from which the rotational speed of the imbalance shaft can be determined and also intermediate positions can be interpolated. Of course, the position sensor can also be designed such that it detects the rotational position of the imbalance shaft and thus their speed permanently. The exact detection of the rotational position is important in order to derive the phase position of the unbalance shaft.

Advantageously, the hydraulic motor associated with an actuator, in particular a hydraulic valve, wherein the individual exciter comprises a controller, for evaluating a signal from the position sensor and for driving the actuator, such that the controller for the unbalance shaft predetermined target speed and / or Target phase position is achieved.

Instead of the hydraulic motor, another suitable individual drive can be used for the individual imbalance shafts of the individual exciter, e.g. a controllable electric motor. At the moment, however, electric motors are still susceptible to vibration and should therefore not have a sufficient service life in view of the strong vibrations.

Thus, each individual exciter has its own control loop, in which the imbalance shaft forms the controlled system and the position sensor forms the measuring element. The position of the imbalance shaft and thus its actual phase position and actual speed is determined with the help of the position sensor and fed as a measured value to the controller. Of course, the evaluation of the signal from the position sensor also take place only in the controller itself to z. B. to determine the IstDrehzahl. On the basis of the values for the setpoint speed or the desired phase position specified for the controller, the controller controls the actuator, in particular the hydraulic valve, so that the assigned hydraulic motor drives the imbalance shaft in the desired manner.

In a particularly advantageous embodiment of the invention, a central control is provided for coordinating the controller of the individual exciter and for prescribing an individual desired speed and / or desired phase position for each controller of the individual exciter, such that a desired by an operator and / or predetermined by a work or driving program behavior of the ground contact plate is achieved.

The central controller, e.g. a process computer, thus has the task of forming the link between the operator and the individual exciters of the vibration exciter device. The operator gives the central control a driving intention for the vibration plate, z. B. Forward, reverse, rotation, lateral or cornering. In the central control corresponding driving programs are assigned to this user request, from which specifications for the individual desired rotational speeds and in particular desired phase positions of the unbalanced shafts in the individual pathogens are derived. These setpoints are fed individually to the regulators of the individual exciters, whereby the regulators of the individual exciters ensure a corresponding behavior of the respective unbalanced shafts.

In another embodiment of the invention, only a "total responsible" central controller is provided instead of the controller of the individual exciter and the parent central control. The central controller is used to evaluate the signals from the individual positioners of the individual exciters and to individually control the actuators of the individual exciter, such that the desired by the operator and / or predetermined by a driving program behavior of the ground contact plate is achieved. In contrast to the more decentralized control structure explained above, the central controller provides centralized control. The central controller centrally detects the behavior of each imbalance shaft and takes the necessary measures to ensure that the imbalance shaft reaches the required rotational behavior. Again, the user request or a predetermined driving program is relevant, after which z. B. a forward or reverse travel of the ground contact plate is required.

In the control of speed and phase position of unbalanced shafts, a peculiarity can be exploited: Due to energetic interactions unbalanced shafts, which are arranged on a common rigid carrier, the desire to synchronize themselves in terms of their speed. The controllers then only have to - corresponding setpoints in particular for the phase position assumed - adjust the changes or difference from the Selbstsynchronisierlage out to achieve the desired relative position or phase position of the imbalance wave concerned.

Preferably, the unbalance shafts of the individual exciters are driven at the same speed. In this way, a behavior of the interacting individual exciters can be achieved, which corresponds to the behavior of known, purely mechanically operating, in particular based on a form-locking coupling of the imbalance waves involved vibration exciters.

Due to the individual controllability of the individual exciters, however, it is also possible in an advantageous manner for the imbalance shaft to be driven by at least one of the individual exciters at a different rotational speed than the imbalance shafts of the remaining individual exciters. In particular, this other speed an odd multiple, z. B. a triple or a fivefold of the rotational speed of the imbalance waves of the remaining individual exciters amount. In this way, in certain applications, a special vibration behavior of the vibration exciter device can be achieved, which would be practically impossible or only with considerable effort realized in purely mechanical vibration exciters with gearboxes. A only temporary deviation of the speed would be almost impossible with purely mechanical vibration exciters, because it would require a manual transmission.

The different rotational speed of at least one of the imbalance shafts may allow for certain applications particularly hard impacts are introduced into the soil.

In a particularly advantageous further development of the invention, at least one of the individual exciters can be controlled in such a way that the imbalance shaft assigned to it specifically reaches a non-uniform rotational speed. Basically, it must be assumed that the rotational speed of an imbalance shaft fluctuates due to the permanent energy exchange between the kinetic energy of the imbalance shaft itself and the soil contact plate acted upon by it. The assigned controller becomes Although always try to keep the speed of the unbalance shaft at the specified value. Due to the high speed, however, it can be assumed that the controller will not be able to compensate for the speed fluctuations for the energy exchange. Rather, it will be sufficient for the normal case to set the mean phase angle and speed of the imbalance shaft to the desired setpoint.

In the embodiment mentioned here, however, the controller has the task of imparting a non-uniform rotational speed in a targeted manner, regardless of the virtually unavoidable speed fluctuation in practice. It could be appropriate that the imbalance shaft specifically reaches different rotational speeds during a revolution to z. B. to allow a longer ground contact of the ground contact plate, so that the impact energy can be effectively introduced into the ground.

In a particularly advantageous embodiment of the invention, a second vibration exciter device acting on the ground contact plate is provided, with at least two unbalanced shafts which are positively coupled to one another and driven in opposite directions. At least one of the imbalance shafts of the second vibration exciter device is associated with a position sensor for determining the phase position of this imbalance shaft. A signal from this position sensor is fed to the central controller or to the central controller in order to coordinate the speed and / or the phase position of the imbalance shafts of the second vibration exciter device with the individual exciters.

In this embodiment, therefore, a "conventional", purely mechanically by positive engagement coupling (gears) working vibration exciter combined with the individual exciters of the vibration exciter device according to the invention described above. This makes it possible to continue to use the purely mechanically operating second vibration exciter device, whose principle of operation has proven excellent over many years. For example, the second vibrator may serve to generate vibrational forces that are used only for forward or reverse travel while achieving force effects for steering or traveling the vibrating plate through the vibrator with the single exciter according to the present invention. In another variant, the only mechanically operating second vibration exciter device is used exclusively to generate vertical compression forces, while the forces for locomotion and steering of the vibrating plate are achieved by the individual exciters of the vibration exciter device according to the invention.

The central controller or the central controller coordinate the behavior of the second vibration exciter device with the individual exciters of the vibration exciter device according to the invention in order to achieve the desired behavior of the ground contact plate.

Preferably, the position sensor has a rotation angle detection device. This makes it possible to precisely detect the position and thus also the speed of an imbalance shaft at any time.

In a further embodiment of the invention, the individual exciters and / or the second vibration exciter device are arranged distributed on a plurality of floor contact plates. The lower mass thus has a plurality of ground contact plates, which are each assigned a purely mechanical second vibration exciter device and / or one or more individual exciters. Here are almost any combination possible. Of course, it is also conceivable to distribute exclusively individual exciters of the vibration exciter device according to the invention on the ground contact plates without a second vibration exciter device must be present.

In a particularly advantageous embodiment of the invention, at least some of the unbalance shafts of the individual exciters are arranged on the ground contact plate such that force vectors generated by them act in different planes. As a result of the rotation of the imbalance shafts, the imbalance masses arranged thereon each generate a centrifugal force vector which rotates in a plane which is perpendicular to the axis of rotation of the imbalance shaft. If the axes of rotation of the imbalance shafts are arranged differently directed on the ground contact plate, accordingly, the force vectors of the imbalance masses act in different planes. Depending on the control of the unbalanced shafts, force effects can be different Directions are generated, which cause a corresponding movement behavior of the ground contact plate.

Preferably, at least some of the imbalance waves of the individual exciters on the ground contact plate are arranged in a star shape, axially, parallel or at an angle to each other on the ground contact plate. Of course, any hybrid forms of these types of arrangements are conceivable to achieve a desired driving and directional behavior of the one or more ground contact plates.

In a further development of the invention, at least one of the unbalanced shafts carries a larger imbalance mass than other unbalanced shafts. Such an embodiment carries z. B. recognition that the vibration plate is used in the predominant case in forward and reverse drive, while rotations and turns and skew more represent the exception or require less force. Accordingly, the individual exciters, which serve for the forward and reverse drive should have unbalanced shafts with greater imbalance mass than the individual exciters, which are only intended to effect a curved or inclined drive.

Fig. 1

einen schematischen Schnitt durch einen erfindungsgemä- ßen Einzelerreger;

Fig. 2

eine erfindungsgemäße Schwingungserregereinrichtung mit zwei Einzelerregern;

Fig. 3

eine Variante einer erfindungsgemäßen Schwingungserrege- reinrichtung mit zwei Einzelerregern;

Fig. 4

eine Draufsicht auf eine Bodenkontaktplatte mit einer erfin- dungsgemäßen Schwingungserregereinrichtung gemäß einer ersten Ausführungsform der Erfindung;

Fig. 5

eine Draufsicht auf eine Bodenkontaktplatte mit einer erfin- dungsgemäßen Schwingungserregereinrichtung gemäß einer zweiten Ausführungsform der Erfindung;

Fig. 6

eine Draufsicht auf eine Bodenkontaktplatte mit einer erfin- dungsgemäßen Schwingungserregereinrichtung gemäß einer dritten Ausführungsform der Erfindung;

Fig. 7

Beispiele für Anordnungen von Einzelerregern.

These and other advantages and features of the invention are explained in more detail below with the aid of the accompanying figures. Show it:

Fig. 1

a schematic section through an inventive individual exciter;

Fig. 2

a vibration exciter device according to the invention with two individual exciters;

Fig. 3

a variant of a vibration generating device according to the invention with two individual exciters;

Fig. 4

a plan view of a ground contact plate with a vibration exciter device according to the invention according to a first embodiment of the invention;

Fig. 5

a plan view of a ground contact plate with an inventive vibration exciter device according to a second embodiment of the invention;

Fig. 6

a plan view of a ground contact plate with a vibration exciter device according to the invention according to a third embodiment of the invention;

Fig. 7

Examples of arrangements of individual pathogens.

As described above, the invention relates to a soil compacting device designed as a vibrating plate, the structure of which is known in principle. An essential component of a vibration plate is a vibration exciter device, which initiates a directed vibration in a ground contact plate. The vibrating ground contact plate acts on the ground to compact it. Furthermore, the resultant total force generated by the vibration exciter device can achieve a longitudinal or transverse propulsion and a steering of the vibrating plate. Since this structure has been known in principle for a long time, a more detailed description is unnecessary.

The vibration plate according to the invention has a vibration exciter device, with at least two individual exciters 13, which act on a ground contact plate 12.

Fig. 1 shows in a sectional view of the schematic structure of an individual exciter 13 according to the invention.

In a z. B. tubular housing 1, an imbalance shaft 2 is rotatably mounted. The imbalance shaft 2 carries an imbalance mass. 3

The imbalance shaft 2 is driven in rotation by a hydraulic motor 4. The hydraulic motor 4 hydraulic fluid is supplied via a hydraulic line 5 from a hydraulic supply, not shown. The hydraulic supply can be arranged at the vibrating plate substantially on the upper mass. Part of the hydraulic supply is z. As a diesel, gasoline or electric power unit that drives a hydraulic pump.

The hydraulic pump generates a hydraulic pressure in a hydraulic fluid that can be stored in a hydraulic accumulator. Furthermore, a hydraulic reservoir for collecting and storing the hydraulic fluid must be provided. Due to the strong vibration effect in the lower mass, it is expedient if most of the components of the hydraulic supply are arranged in the upper mass vibrationally decoupled from the lower mass. As a result, it is only necessary to establish a connection from the hydraulic supply to the hydraulic motor 4 by means of the hydraulic line 5.

Downstream of the hydraulic motor 4, a hydraulic valve 6 serving as an actuator is arranged, which controls the hydraulic outflow to the hydraulic motor 4 and thus influences the rotational speed of the hydraulic motor 4. Of course, the hydraulic valve 6 can also be arranged upstream of the hydraulic motor 4.

At a the hydraulic motor 4 opposite end of the imbalance shaft 2, a position sensor 7 is arranged. The position sensor 7 - z. B. a rotation angle detecting device - is able to detect the position of the imbalance shaft 2 in at least one position. This can be z. B. optical, magnetic, inductive or capacitive. From the possibility of detecting their position at least once during one revolution of the imbalance shaft 2, the rotational speed and the phase position of the imbalance shaft 2 can be determined. Furthermore, it is readily possible to determine by interpolation over time with sufficient accuracy, the position of the imbalance shaft 2 at any time. The position of the imbalance shaft 2 is therefore important because the imbalance mass 3 carried by it generates a strong centrifugal force during rotation. The centrifugal force of the unbalanced mass 3 interacts with the centrifugal forces of the other, belonging to the vibration exciter device single exciters 13 and thus produces a total resulting force action, which determines the movement behavior of the acted upon by the individual exciters 13 ground contact plate 12. Only when both the speed of the unbalanced shafts 2 and their phase positions are precisely coordinated with each other, the ground contact plate 12 can move in the desired manner.

The vibration exciter device according to the invention has at least two of these individual exciters 13, which are arranged in a suitable manner on the ground contact plate 12. Regarding the possible arrangement forms will be commented later.

The in Fig. 1 shown individual exciter 13 also has a controller 8, which evaluates a signal generated by the position sensor 7, and at least determines the speed and / or the position of the imbalance mass 3 with respect to a specific time (phase).

The controller 8 receives beyond - as will be explained later - a setpoint signal 9, with which the required setpoint speed or target phase position is specified. The controller 8 accordingly controls the hydraulic valve 6 in order to achieve the desired rotational speed and phase position of the imbalance shaft 2 or imbalance mass 3 with the aid of the hydraulic motor 4.

Fig. 2 shows the schematic structure of the vibration exciter device according to the invention with two individual exciters 13 according to Fig. 1 , The individual exciters 13 are in Fig. 2 arranged parallel to each other.

A central controller 10 is provided, which specifies setpoint signals 9 for each of the controllers 8 of the individual exciters 13. Each controller 8 then ensures in the manner described above for its associated individual exciter 13, that the imbalance shaft 2 behaves in the desired manner.

The setpoint signals 9 predefined by the central controller 10 may differ for each of the individual exciters 13. Essential differentiation parameters are setpoint speed, setpoint phase position and setpoint direction of rotation. The change of the direction of rotation is optional and requires an additional construction cost in the realization of the hydraulic motor 4 and the hydraulic valve 6. Normally, a change in the direction of rotation will not be required.

In Fig. 2 By way of example, two individual exciters 13 are shown. Of course, it is readily possible to provide a vibration exciter device according to the invention with more than two individually controllable individual exciters 13.

Fig. 3 shows another embodiment of the invention, wherein also the vibration exciter device is shown with two single exciters 13.

In contrast to those associated with the Fig. 1 and 2 described single pathogens have the individual pathogens Fig. 3 no individually assigned controller 8. Rather, the signals of the position sensor 7 are guided to a central controller 11, which evaluates all signals from all the individual exciters 13. The central controller 11 then controls individually corresponding to each of the hydraulic valves 6 to individually achieve the desired behavior of the unbalanced shaft 2 for each of the individual exciter 13.

In this embodiment, the construction cost due to the fact that only a single regulator is required, be less than that in the Fig. 1 and 2 illustrated embodiment. This in turn offers the advantage that the individually assigned controller 8 allows a very fast small loop.

The central controller 10 and the central controller 11 include appropriate work or driving programs, with which the operator via controls (remote control, control lever, buttons) given wishes for the driving and vibration behavior of the vibrating plate can be converted into control specifications for the individual exciter 13. Wishes the operator z. B. a transition from the state of compression of the vibrating plate in a forward drive, the central controller 10 and the central controller 11 causes an adjustment of the phase position in at least one of the individual exciter 13, whereby the resulting total force changes its direction of action.

For a reliable normal operation, it is desirable that the unbalanced shafts 2 rotate as far as possible exactly at the same speed. However, in addition, since the position of the imbalance shaft 2 is constantly monitored, speed deviations can be corrected at any time, so that the desired phase position between the imbalance shafts is maintained. A progressive deviation of the speed is thus excluded.

Serving as an actuator for the control of the speed and the phase position of the imbalance shaft 2 hydraulic valve 6 should be able to quickly to be switched. In practice, various solutions are complementary or alternative to the in Fig. 1 shown embodiment:

The hydraulic valve 6 can also be arranged upstream in the inlet of the hydraulic motor 4. It should be a fast proportional valve. In a multi-way valve, it is possible to rigidly clamp the hydraulic motor 4 and in this way the imbalance shaft 2 for a certain time not to participate in the vibration generation.

Furthermore, a plurality of hydraulic motors 4 can be supplied via a Hydrauliksynchronisierblock with the same amount of oil. Alternatively, each hydraulic motor 4 can be assigned an individual hydraulic pump. The correction of the rotational speed and phase position of the imbalance shaft takes place with the aid of smaller, individually assigned metering or discharge valves, which slightly increase or decrease the volume flow of hydraulic fluid to the hydraulic motor or away from the hydraulic motor 4.

In addition, a proportional valve can be arranged in front of the hydraulic synchronizing block in order to adapt the speed of the entire system to the requirements. The Hydrauliksynchronisierblock can also be replaced by comparatively slow, individually designed metering valves.

Furthermore, it is possible to provide quickly switched on / off valves - also in combination with one of the variants described above. If several fast on / off valves are switched in parallel, a proportionality can be reproduced in a stepped manner.

Likewise, the hydraulic motor 4 and the hydraulic valve 6 can be replaced by an adjusting hydraulic motor, which is directly controlled by the controller 8. Furthermore, for each unbalanced shaft 2, an individually associated adjusting hydraulic pump can be provided.

Because of the high vibration amplitudes at the lower mass, it is not appropriate to arrange electromagnetic valves there. These would have to be provided in each case on the upper mass. However, already today vibration-resistant valves are under development, such. B. piezo valves or magnetic fluid valves, which - if they prove themselves in practice - could be arranged very close to the hydraulic motor 4. In this way, inaccuracies would be eliminated by the compressibility of the hydraulic fluid and the elasticity of the lines.

Fig. 4 shows a schematic representation of a plan view of a ground contact plate 12, on which four individual exciters 13 are arranged at an angle to each other. By appropriate control of the individual exciter 13 can be a nearly random handling of the ground contact plate 12 in the forward, backward and transverse directions and a rotation in the state and cornering reach.

The Fig. 5 and 6 show further embodiments of the invention in the form of differently arranged individual exciters 13 on the ground contact plate 12. The individual exciters 13 are star-shaped ( Fig. 5 ), axial ( Fig. 5 ), parallel ( Fig. 5 and 6 ) or angled ( 4 to 6 ) are arranged on each other on the ground contact plate.

In the choice of the arrangement to the expert are almost any options available because he no longer, as before, must consider the mechanical coupling of the unbalanced shafts of the vibration exciter. Rather, he can arbitrarily arrange each a complete unit representing individual exciter 13 on the ground contact plate 12. For him then there is only the problem to program the controller in the form of the central controller 10 or the central controller 11 in a suitable manner to accommodate the arrangement of the individual exciter 13.

Fig. 7 shows further possibilities of the arrangement of the individual exciter 13 on the ground contact plate 12. For simplicity, the individual exciters 13 are shown only as dashes.

In Fig. 7a ) Accordingly, the imbalance waves of the individual exciters 13 are partially parallel; axially displaced, coaxial and / or partially arranged at an angle to each other.

In Fig. 7b ) In addition to the "normal" single exciters 13 reinforced single exciters 14 are provided, which is an imbalance shaft with larger imbalance mass exhibit. Accordingly, the amplified individual exciters 14 are not symbolized as lines, but as elongated boxes.

The reinforced individual exciters 14 can be used primarily to achieve an increased compression effect or a more rapid forward and reverse travel. Accordingly, the "normal" individual exciter 13 and the individual exciters are provided with lower imbalance masses for the steering of the vibrating plate. However, provided with the amplified individual exciters 14 unbalanced shafts with increased imbalance masses can be replaced by "normal" individual exciter 13, if z. B. several individual exciters 13 are arranged one behind the other in parallel.

In Fig. 7c ), an embodiment is shown symbolically, in which instead of a ground contact plate 12, three sub-ground contact plates 12a, 12b, 12c are provided which each carry individual exciters 13 and which are connected to each other via connecting members 15. As a result, a relatively large vibrating plate can be realized, which nevertheless can be moved easily in the terrain due to the flexibility that can be achieved in the terrain by the divided and relatively movable floor contact plates 12a to 12c.

The central controller 10 and the central controller 11 make it possible to understand predetermined programs and thereby perform defined driving conditions. This includes driving straight ahead and backward, standing shaking or cornering. With more than four independently controllable individual exciters 13, it is also possible to adjust the movement of the lower mass by changing the angular positions of the unbalanced shafts to each other such that the impact of the ground contact plate 12 is parallel to the ground or targeted as edge impact, in which an edge or even only one corner first touches the ground and then only the remaining bottom of the ground contact plate 12 strikes. For the central controller 10 or the central controller 11, intelligent controllers with fuzzy logic and / or adaptive behavior are to be preferred in order to allow adaptation to the actual ground and terrain conditions.

Claims (15)

1. Vibration plate for ground compaction, having

   - an upper mass comprising a drive;

   - a lower mass comprising at least one ground-contacting plate (12);

   - a vibration excitation device which has at least two individual exciters (13) and influences the ground-contacting plate (12);
   characterised in that

   - the individual exciters (13) each comprise an individual unbalanced shaft (2) which supports an unbalanced mass (3) and is driven individually; and in that

   - the individual exciters (13) can be controlled individually with respect to the rotational speed and/or the phase position of the respectively allocated unbalanced shaft (2).
2. Vibration plate as claimed in Claim 1, characterised in that each of the individual exciters (13) comprises a hydraulic motor (4) or electric motor which rotationally drives the unbalanced shaft (2), and a position sensor (7) which detects the position of the unbalanced shaft (2) in at least one location.
3. Vibration plate as claimed in Claim 1 or 2, characterised in that

   - a control member (6), in particular a hydraulic valve, is allocated to the hydraulic motor (4);

   - the individual exciter (13) comprises a regulator (8) for evaluating a signal from the position sensor (7) and for controlling the control member (6) such that a desired rotational speed and/or desired phase position which is/are provided to the regulator (8) for the unbalanced shaft (2) is/are achieved.
4. Vibration plate as claimed in any one of Claims 1 to 3, characterised in that a central controller (10) is provided to co-ordinate the regulators (8) of the individual exciters (13) and to provide an individual desired rotational speed and/or desired phase position for each regulator (8) of the individual exciters (13) such that the ground-contacting plate (12) can function in a manner desired by an operator and/or predetermined by a operating or driving program.
5. Vibration plate as claimed in Claim 1 or 2, characterised in that

   - a control member (6), in particular a hydraulic valve, is allocated to the hydraulic motor (4);

   - a central regulator (11) is provided to evaluate the signals from the position sensors (7) of the individual exciters (13) and to individually control the control members (6) of the individual exciters (13) such that the ground-contacting plate (12) can function in a manner desired by an operator and/or predetermined by a operating or driving program.
6. Vibration plate as claimed in any one of Claims 1 to 5, characterised in that the unbalanced shafts (2) of the individual exciters (13) are driven at the same rotational speed.
7. Vibration plate as claimed in any one of Claims 1 to 5, characterised in that the unbalanced shaft (2) of at least one of the individual exciters (13) is driven at a different rotational speed than the unbalanced shafts (2) of the remaining individual exciters (13).
8. Vibration plate as claimed in Claim 7, characterised in that the other rotational speed is an odd multiple of, in particular three-times or five-times, the rotational speed of the unbalanced shafts (2) of the remaining individual exciters (13).
9. Vibration plate as claimed in any one of Claims 1 to 8, characterised in that at least one of the individual exciters (13) can be controlled such that the unbalanced shaft (2) allocated thereto achieves a non-uniform rotational speed in a controlled manner.
10. Vibration plate as claimed in any one of Claims 1 to 9, characterised in that

    - a second vibration excitation device is provided which influences the ground-contacting plate (12) and has at least two unbalanced shafts which are driven in opposite rotational directions to each other and are coupled together in a positive-locking manner;

    - a position sensor is allocated to at least one of the unbalanced shafts of the second vibration excitation device to determine the phase position of this unbalanced shaft;

    - a signal of this position sensor is supplied to the central controller (10) or to the central regulator (11) to co-ordinate the rotational speed and/or the phase position of the unbalanced shafts of the second vibration excitation device with the individual exciters (13).
11. Vibration plate as claimed in any one of Claims 1 to 10, characterised in that the position sensor (7) comprises an angle of rotation detection device.
12. Vibration plate as claimed in any one of Claims 1 to 11, characterised in that the individual exciters (13) and/or the second vibration excitation device are disposed distributed on several ground-contacting plates (12a, 12b, 12c).
13. Vibration plate as claimed in any one of Claims 1 to 12, characterised in that at least some of the unbalanced shafts (2) of the individual exciters (13) are disposed on the ground-contacting plate (12) such that force vectors produced thereby act in different planes.
14. Vibration plate as claimed in any one of Claims 1 to 13, characterised in that at least some of the unbalanced shafts (2) of the individual exciters (13) are disposed on the ground-contacting plate (12) in a star-like, axial, parallel or angular manner with respect to each other.
15. Vibration plate as claimed in any one of Claims 1 to 14, characterised in that at least one of the unbalanced shafts (2) supports a greater unbalanced mass (3) than the other unbalanced shafts.

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