EP1980671B1 - Soil compacting device in form of a vibration plate - Google Patents

Description

• einem Bodenkontaktelement, mit dessen Unterseite Verdichtungskräfte in zu bearbeiteten Untergrund einleitbar sind, wobei die Verdichtungskräfte hervorrufende Schwingungen des Bodenkontaktelements von einem damit verbundenen und mittels eines Hydraulikmotors angetriebenen Schwingungserregers erzeugbar sind, mit dem auch eine Fortbewegung des Bodenverdichtungsgeräts in eine Richtung parallel zu dem Untergrund erzeugbar ist, und
• einem Oberwagen, der eine Antriebseinrichtung für eine Hydraulikpumpe zur Versorgung des Hydraulikmotors mit unter Druck stehender Hydraulikflüssigkeit aufweist und des Weiteren mit einem Führungselement für eine Bedienperson versehen ist,

wobei das Führungselement mit mindestens einem Bedienelement ausgestattet ist, das mindestens ein vorzugsweise weglos arbeitendes Sensorglied aufweist, mit dem ein Stellmittel betätigbar ist, mit dem die Fortbewegung des Bodenverdichtungsgeräts unterbrechbar ist, wenn das mindestens eine Sensorglied die Abwesenheit eines Körperteils der Bedienperson signalisiert.The invention relates to a soil compaction device in the form of a vibrating plate

• a ground contact element, with the underside of compression forces can be introduced into the substrate to be machined, wherein the compression forces inducing vibrations of the ground contact element of an associated and driven by a hydraulic motor vibrator can be generated, with a movement of the soil compaction device in a direction parallel to the ground can be generated , and
• an uppercarriage having a drive device for a hydraulic pump for supplying the hydraulic motor with pressurized hydraulic fluid and further provided with a guide element for an operator,

wherein the guide element is equipped with at least one control element having at least one preferably weglos working sensor member with which an actuating means is actuated, with the locomotion of the soil compaction device is interrupted when the at least one sensor member signals the absence of a body part of the operator.

State of the art

Such a soil compacting device is for example from the EP 1 101 027 B1 (equivalent to WO 2000/006879 A1 ) known. In the working device described therein, capacitive or optical proximity switches or touch-sensitive grip elements are provided on a handle of the device with which it can be detected whether the handle is properly held by the operator. This "hold control" serves to detect a particular danger, in particular during a so-called "special operating state", namely, for example, when starting or when improperly guided or during a Pehlpositionierung of the device. In such special operating states endangering the operator, detection of a deviation from proper holding of the device now results in the engine speed of the drive motor used to drive the device being reduced to a safety speed below an operating speed. With a like that said "deadman circuit" is to prevent an uncontrolled working and moving device endangers the operator or third parties.

Furthermore, in the EP 0 242 809 A1 nor described a feasible on a handle vibration plate in which below the handle, a so-called additional "dead man's hand grip" is present, which is coupled to the throttle cable. In order to bring the motor of the vibrating plate to an operating speed, the operator must pivot the dead man's handle upwards and hold it against the actual operating handle. Should for any reason the operator let go of the dead man's handle, this moves down due to its own weight and reduced via the throttle cable, the engine speed to an idle speed, regardless of whether the actual speed controller another speed is selected. A disadvantage of these "mechanical deadman handles" is the heavy operability, since always an additional holding force is needed, which makes the actual operation process difficult.

In all known deadman circuits, it appears as a disadvantage in appearance that passes when the engine speed is adjusted to a standstill of the device or to a reduction of the movement to a safe level too long a period. The internal combustion engine and the downstream remaining drive train including the moving masses of the device itself have namely a not inconsiderable inertia, so that a non-negligible time lag of the device occurs, which still represents a hazard to the operator or third parties.

A soil compaction device according to the preamble of claim 1 is made EP 1 722 036 A2 known.

task

The invention has for its object to further develop a soil compaction device in the form of a vibrating plate such that the period is shortened from detection of an emergency situation to the actual standstill of the device or to reduce the movements performed by the device to a safe level.

solution

Based on a compression plate of the type described above, this object is achieved in that the actuated by the sensor member actuating means causes an interruption of the supply of the hydraulic motor with hydraulic fluid.

In contrast to the known devices in which the interruption function on the drive means, i. typically an internal combustion engine, acts and thus attaches to the beginning of the entire drive train, is the point of intervention of the inventively initiated interruption measure in the hydraulic circuit. In this way, the inertia of the drive motor and the hydraulic pump can be turned off, so that the lag times compared to the prior art can be significantly reduced. As a result, the safety is increased for both the operator and for third parties and the current requirements for occupational safety taken into account. Although so far, according to the legal regulations, a dead man's circuit with vibration plates is not mandatory at all. Nevertheless, the safety margin when using the inventive concept is particularly high, since the response times are very low until the vibration plate stops. This makes it possible, for example, to let even inexperienced people work with such a vibrating plate, which is especially for landlords such soil compaction of interest.

According to one embodiment of the invention it is proposed that the adjusting means is a hydraulic valve with which the hydraulic fluid from a flow line via a bypass line without pressure in a tank is diverted. While the bypass line is closed by the hydraulic valve in the regular operating operation of the device, so that the hydraulic fluid is supplied to the hydraulic motor under pressure, there is a short circuit to the detection of a "fault", so that the then pressureless hydraulic motor comes to a very short time to a standstill.

Advantageously, the hydraulic valve is an electromagnetically operated 2/2-way valve, which is biased by spring force in an open position.

In order to always achieve a "safe state" in the event of a breakdown or malfunction in the on-board electrical system, the hydraulic valve should release the connection to the tank in the de-energized state of its electromagnet. On the other hand, this means that a regular working operation is possible only when the exciter coil of the valve drive is current-carrying, i. the on-board electrical system is in operation.

A particularly preferred development of the device according to the invention is that the at least one sensor element changes in the stray capacitance of a body part, in particular a hand clutching operator. Such capacitive sensor elements for use in dead man's devices are known, for example, from US 5,178,237 DE 102 19 386 A1 known. These sensor elements, which are easy to incorporate into handles, have proven themselves well in practice, in particular in harsh agricultural operations.

An alternative operating principle for a sensor member is from the DE 198 43 666 A1 in which the sensor element is designed such that due to the pressure exerted by an operator in a defined gripping area, it changes an electrical quantity which is used to output a control signal.

In order to make it easier for an operator to guide the vibrating plate according to the invention, it is proposed to provide two operating elements in the form of one handle each on the guide element of the vibrating plate, wherein each handle should have a sensor element. In this case, there is a particularly useful connection of the two sensor elements is that the supply of the hydraulic motor with hydraulic fluid is interrupted only when both sensor members signal the absence of the hand of the operator. In such an embodiment, it is thus sufficient for a properly defined as device management when the operator holds either the right or the left hand or both hands on the respectively provided handle with integrated sensor element. Only when both hands are not at the intended location, it is assumed that an emergency, so that then triggers the deadman circuit and leads to equipment standstill.

The invention further ausgestaltend is finally still provided that the vibration plate has an electrical on-board system with a power supply, in particular a generator and a chargeable battery accumulator. In the event that no power supply is available in a device, although the structure of the deadman circuit according to the invention is also possible in principle, but the selection of usable sensor elements is then severely limited.

embodiment

The invention will be explained in more detail with reference to an embodiment which is illustrated in the drawing.

Fig. 1

eine schematische Seitenansicht eines Bodenverdichtungsgeräts in Form einer Vibrationsplatte,

Fig. 2

eine vergrößerte perspektivische Darstellung des Endbereichs einer Führungsdeichsel mit zwei Handgriffen,

Fig. 3

einen hydraulischen Schaltplan der Totmann-Schaltung und

Fig. 4

einen elektrischen Schaltplan der Totmann-Schaltung.

It shows:

Fig. 1

a schematic side view of a soil compaction device in the form of a vibrating plate,

Fig. 2

an enlarged perspective view of the end portion of a guide bar with two handles,

Fig. 3

a hydraulic circuit diagram of the deadman circuit and

Fig. 4

an electrical circuit diagram of the deadman circuit.

An in FIG. 1 illustrated soil compaction device 1 in the form of a vibrating plate has a plate-shaped bottom contact element 2, with the underside 3, the device stands up on a substrate to be compacted. In the ground contact element 2, a vibration exciter 4 is integrated, which can be seen on the basis of the three bulges for its exciter waves.

Coupled via not shown elastic elements 5 in the front and rear of the ground contact element 2 is located above the latter a so-called superstructure 6. This contains on the one hand an internal combustion engine, not shown, which serves as a drive device for a likewise located in the superstructure 6 hydraulic pump. The internal combustion engine is put into operation by means of an invisible electric starter and supplied with fuel via a fuel tank 7.

Also not shown are hydraulic lines, which lead from the hydraulic pump to a located in the ground contact element 2 and laterally flanged to the vibration exciter 4 hydraulic motor.

In order to operate the vibrating plate as a hand-held device, this has a guide device 8 in the form of a drawbar at the free end of which is a control element 9 in the form of a C-shaped handle bar.

As is apparent from the enlarged view according to FIG. 2 results, is at the mutually facing free ends of the control element in each case a designed as a handle sensor member 10, which operates on a capacitive measuring principle. Each of the two handles Detects if an operator holds her hand on the handle or not. When removing the hand of a handle of this signal via a non-visible signal line within the operating element designed as a tube 9 and within the drawbar designed as a hollow profile signal to an electronic control unit, not shown. The operation of the deadman circuit in electrical terms is in the circuit diagram according to FIG. 4 explained in more detail later. FIG. 2 also shows a throttle lever 11, which can be taken by pivoting influence on the engine speed of the engine. The throttle lever 11 or the engine speed at all, however, are unaffected by the deadman circuit according to the invention. Other controls of the soil compaction device 1, such as a forward-reverse circuit and a steering lever for adjusting "cornering right" and "cornering left" are prior art and are therefore not explained in detail here.

The hydraulic circuit diagram according to FIG. 3 illustrates that of a controllable internal combustion engine 12 via a rigid coupling 13, a hydraulic pump 14 is drivable. In the regular working operation of the device, the hydraulic pump 14 conveys the suctioned via a suction line 15 from a tank 16 hydraulic fluid into a flow line 17, which leads with a sub-strand 17.1 to a hydraulic motor 18, this serves to drive the in FIG. 3 not shown vibration exciter, which is located in the ground contact element 2 of the vibrating plate. Via a return line 19, the hydraulic fluid flows back into the tank 16 without pressure.

At a junction 20 is from the flow line 17 from a bypass line 21 which leads into the tank 16 and in which there is a hydraulic valve 22 in the form of a 2/2-way valve, which is actuated by means of an electromagnet 23. In FIG. 3 is the hydraulic valve 22 is shown in a position in which the solenoid 23 is not energized, so that the valve is brought by spring force in a position in which of the flow line 17, a connection to the bypass line 21 is open, so that the hydraulic fluid from the hydraulic pump 14 can flow in the short circuit in the tank 16. This switching state is assumed when both sensor members 10 (handles) on the drawbar signal that there is no contact with the hands of the operator. The electronic control unit that works in FIG. 3 is not shown, then ensures that the armature of the electromagnet 23 drops and thus causes the Ö1 short circuit, whereby the hydraulic motor 18 stops for lack of oil supply. On the other hand, the armature of the electromagnet 23 attracts - what the presence at least a hand on a sensor member 10 requires - so closes the hydraulic valve 22 again and from the still running hydraulic pump 14 (the engine 12 is not affected by the deadman circuit) hydraulic fluid is again pumped to the hydraulic motor 18, which thus starts again.

In the left part of the picture FIG. 3 is yet another sub-strand 17.2 of the flow line 17 shown, which leads to a so-called Orbitrol 24, with the two side of the vibrator 4 arranged hydraulic actuating cylinder 25 (only indicated schematically) are controlled. With the help of Orbitrols 24 and the actuating cylinder 25 can be both forward drive and reverse drive the vibrating plate and (optional) between "cornering right" and "cornering left", The Orbitrol 24 with the associated actuating cylinders 25 is state of the art and therefore devoid at this point more detailed explanations.

The in FIG. 4 shown electrical circuit diagram can be taken from the wiring diagram of deadman circuit in electrical terms. A lead-acid battery 26 supplies an electronic control unit 28 with voltage via an ignition switch 27. Via a line 29, the controller 28 is connected to the ground of the soil compaction device 1. An idle switch 32 located in a conduit 31, which is operated by a handle on the drawbar of the vibrating plate, allows the engine to enter the idling state.

Of each sensor member 10 on the two handles each leads a line 33 to the electronic control unit, so that it has the signals regarding the occupancy of the handles. Via a further outgoing from the electronic control unit 28 line 34, the solenoid 23 of the hydraulic valve 22 is then supplied with power when there is hand contact on at least one of the handles. Otherwise, the voltage drops in the line 34 and the hydraulic valve 22 takes due to spring preload in FIG. 4 shown safety position in which it forms a short circuit between the flow line 17 and the tank 16 via the bypass line 21. The pressure on the hydraulic motor 18 drops immediately and the locomotion of the soil compaction device 1 stops.

LIST OF REFERENCE NUMBERS

1

Soil Compactor

2

Ground contact element

3

bottom

4

vibration exciter

5

elastic element

6

superstructure

7

Fuel tank

8th

guide element

9

operating element

10

sensor element

11

throttle

12

internal combustion engine

13

clutch

14

hydraulic pump

15

suction

16

tank

17

supply line

18

hydraulic motor

19

Return line

20

branch

21

bypass line

22

hydraulic valve

23

electromagnet

24

Orbitrol

25

actuating cylinder

26

Bleiakku

27

ignition switch

28

control unit

29

management

30

Dimensions

31

management

32

Idle switch

33

management

34

management

Claims (6)

1. A soil compacting device (1) in the form of a plate vibrator with

   - a soil contact element (2) with the underside (3) of which compacting forces can be introduced into the subsoil to be worked, wherein vibrations of the soil contact element (2) causing the compacting forces are generatable by a vibration exciter (4) that is connected to and driven by means of a hydraulic motor (18), with which locomotion of the soil compacting device (1) in a direction parallel to the subsoil is also generatable, and

   - with an upper car (6), which comprises a drive device for a hydraulic pump (14) for supplying the hydraulic motor (18) with pressurised hydraulic fluid and furthermore is provided with a guiding element (8) for an operating person,

   wherein the guiding element (8) is equipped with at least one operating element (9), which comprises at least one preferentially pathless operating sensor member (10), with which a hydraulic valve (22) is actuatable, with which the hydraulic fluid can be redirected from an advance line (17) via a bypass line (21) into a tank (16) without pressure, the locomotion of the soil compacting device (1) being thus interruptible, wherein the hydraulic valve (22) brings about an interruption of the supply of the hydraulic motor (18) with hydraulic fluid, characterized in that the hydraulic valve (22) is an electromagnetically actuated 2/2-way valve, which is preloaded into an opening position by means of spring force, and in that with the hydraulic valve (22) locomotion of the soil compacting device (1) is interruptible when the at least one sensor member (10) signals the absence of a body part of the operating person.
2. The soil compacting device according to claim 1, characterized in that the hydraulic valve (22) in the currentless state opens the connection to the tank (16).
3. The soil compacting device according to any one of the claims 1 to 2, characterized in that the at least one sensor member detects changes in the stray capacitance of a body part, in particular of a hand, of the operating person.
4. The soil compacting device according to any one of the claims 1 to 3, characterized by two operating elements (9) in the form of hand grips, wherein each hand grip comprises a sensor member (10).
5. The soil compacting device according to claim 4, characterized in that the supply of the hydraulic motor (18) with hydraulic fluid is interruptible only in particular when both sensor members (10) signal the absence of the hand of the operating person.
6. The soil compacting device according to any one of the claims 1 to 5, characterized by an electrical on-board system with a voltage supply, in particular a generator, and an accumulator (26) that is rechargeable by the same.

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