EP4134490A1 - Gripper device and method for operating a gripper device - Google Patents

Abstract

The invention relates to a method for operating a gripper device with a carrier device and a cable gripper arranged thereon, which has a gripper frame, which is held on the carrier device via a retaining cable, at least two gripper shovels, which can be pivoted at a lower end of the gripper frame between a closed position and an open position are mounted, and has an actuating device with an actuating cable for pivoting the grab scoops, with an actuating cable being routed from the carrier device to the actuating device and the carrier device having a driven first cable winch for the retaining cable and a driven second cable winch for the actuating cable, the carrier device having a Undercarriage and an upper carriage rotatably mounted on it about a vertical axis with a boom arm on which the cable gripper is mounted vertically adjustable, wherein to form a slot in the ground in a removal step of rope gripper with open gripper scoops is lowered into the ground by means of the tether, the gripper scoops are closed to remove and pick up soil material, the cable gripper is pulled out of the ground by means of the tether and pivoted by rotating the upper carriage to an emptying position at which the gripper scoops can be released of the picked up soil material are opened and then the cable grab is moved back into the soil slot to repeat the excavation step. According to the invention, a control device is provided with which rotation of the upper carriage to the emptying position and opening and closing of the grab shovels to discharge the soil material or rotation of the upper carriage from the emptying position back to the bottom slot are automatically controlled.

Description

The invention relates to a method for operating a gripper device with a carrier device and a cable gripper arranged thereon, which has a gripper frame, which is held on the carrier device via a retaining cable, at least two gripper shovels, which can be pivoted at a lower end of the gripper frame between a closed position and an open position are mounted, and has an actuating device with an actuating cable for pivoting the grab scoops, with an actuating cable being routed from the carrier device to the actuating device and the carrier device having a driven first cable winch for the retaining cable and a driven second cable winch for the actuating cable, the carrier device having a Has an undercarriage and a superstructure rotatably mounted thereon about a vertical axis with a cantilever arm on which the cable gripper is mounted so that it can be adjusted vertically, wherein to form a slot in the ground in a removal step of rope gripper with open gripper scoops is lowered into the ground by means of the retaining cable, the gripper scoops are closed to remove and pick up soil material, the cable gripper is pulled out of the ground by means of the retaining cable and/or the actuating cable and is pivoted to an emptying position by rotating the superstructure which opens the grab buckets to discharge the collected soil and then moves the cable grab back into the soil slot to repeat the excavating step, according to the preamble of claim 1.

The invention further relates to a gripper device with a carrier device and a cable gripper arranged thereon, which has a gripper frame which is held on the carrier device via a retaining cable, at least two gripper shovels which are pivotably mounted at a lower end of the gripper frame between a closed position and an open position, and an actuating device with an actuating cable for pivoting the grab buckets, with an actuating cable being routed from the carrier device to the actuating device and the carrier device having a driven first cable winch for the retaining cable and a driven second cable winch for the actuating cable, the carrier device having an undercarriage and a has an upper carriage mounted thereon such that it can rotate about a vertical axis and has a cantilever arm on which the cable gripper is suspended in a vertically adjustable manner, according to the preamble of claim 8.

Grab devices are used in foundation engineering to create slots in the ground. Diaphragm walls can be created in the slits to support and/or seal building pits.

Grab devices essentially comprise a grab with grab buckets, the grab being suspended via a tether on a carrier device, typically a jib crane. A grab can be lowered into the ground with the tether. By closing the grab shovels, soil material can be removed and picked up in the grab. The gripper is then pulled back out of the ground using the retaining cable and/or actuating cable and pivoted with the carrier device to an emptying position at which the gripper shovels are opened to discharge the soil material. The gripper is then pivoted back into the working position and inserted into the slot in the floor for a new gripping process.

There are two different types of grabs used on such grab devices, namely hydraulic grabs and cable grabs. A so-called hydraulic gripper is, for example, from the EP 3 798 367 A1 known. In the case of a hydraulic grab, the movement for opening and closing the grab buckets is generated by a hydraulic cylinder which is arranged on the grab frame. Such hydraulic grippers can be operated and controlled relatively easily by the hydraulic system. However, appropriate hydraulic lines are required for supplying and removing hydraulic fluid, which run parallel to the tether. Appropriate cable drums for the hydraulic lines with appropriate winch drives and an appropriately designed hydraulic system are to be provided on the carrier device. As a result, the gripper device is correspondingly enlarged and also more expensive. The hydraulic system also requires additional maintenance.

In contrast, so-called rope grabs offer a significantly simplified structure. Such a rope gripper is, for example, from GB 2 126 981 A known. With a rope grab, the opening and closing movement of the grab buckets is effected by an actuating rope. The actuating cable runs essentially parallel to the retaining cable from the actuating device of the grab shovels to the carrier device. By means of a separate winch for the actuation cable, the grab scoops can be opened or closed by unwinding or winding the actuation cable onto the winches.

In the case of a cable grab, the time-consuming feed of hydraulic lines to the grab can be omitted. Only an additional operating cable with a corresponding winch is to be provided. Such an actuating cable is also considerably less maintenance-intensive than hydraulic lines with a corresponding hydraulic system.

However, operating a rope grab is not as easy as operating a hydraulic grab and requires an experienced machine operator. One reason for this is that due to the double arrangement of a non-rotation-free cable, namely the retaining cable and the actuating cable, torques are generated in different operating states, which cause a certain twisting of the cable gripper about its longitudinal axis. However, an exact rotational position of the cable gripper is essential in order to be able to safely move the cable gripper between the emptying position and a working position in which the cable gripper is driven into the ground to create a slot.

A rotational position of the cable gripper about its longitudinal axis can be brought about by a machine operator by applying specific tensile forces to the retaining cable and the actuating cable. This requires a relatively sensitive operation of the corresponding cable winches. This requires a certain amount of experience from the machine operator and also a high level of concentration when carrying out the process. In addition, cable winches are often operated using foot pedals, so that sensitive operation of the cable winches over several hours is also very tiring for a machine operator.

The invention is based on the object of specifying a method for operating the gripper device and a gripper device in which the gripper device has a simple structure and at the same time simple operation is made possible.

The object is achieved on the one hand by a method having the features of claim 1 and on the other hand by a gripper device having the features of claim 8 . Preferred embodiments of the invention are specified in the respective dependent claims.

The method according to the invention is characterized in that a control device is provided with which rotation of the upper carriage to the emptying position and opening of the grab shovels to discharge the soil material and/or rotation of the upper carriage from the emptying position back to the bottom slot are automatically controlled. In this way, the gripper device can rotate about its vertical axis.

A basic idea of the invention is to provide a control device by means of which on the one hand a rotary drive for the superstructure and on the other hand at least one cable winch for the actuating cable are controlled in a coordinated manner. As a result, a quick and efficient movement of the rope gripper and emptying at the emptying position can be achieved. Elaborate manual control by a machine operator and the coordination of the control of the rotation of the superstructure and/or the gripper device with the actuation of the cable winch for the actuating cable and the cable winch for the retaining cable with the foot pedals that are usually present can be omitted. This provides a significant relief machine operator, both physically and in terms of coordination, especially since a simply constructed cable gripper tends to oscillate, i.e. to vibrate and/or twist. The invention allows a rope gripper to be operated safely and efficiently, even by a less experienced machine operator.

Alternatively or additionally, according to the invention, the superstructure can be rotated from the emptying position back to the slot in the floor. The repetitive movement of the cable gripper from the working position at the bottom slot to the emptying position and back can thus be carried out completely, almost completely or at least partially automatically by the control device. In this case, a first process can first be carried out manually by a machine operator, while a corresponding automatic program is created by the control device in a teach-in process. After the automatic program has been saved, it can be repeatedly executed automatically, resulting in considerable relief for the machine operator.

According to a variant of the invention, a particularly efficient emptying is achieved in that the control device opens the gripper scoops while the cable gripper is still in a pendulum movement due to the twisting of the superstructure. In this way, a dynamic emptying process can be achieved in which the rope gripper does not swing out over the emptying point. This means a significant acceleration of the work process. The pendulum movement of the cable grab can be caused not only by the twisting of the superstructure, but also by the actuation of the cable winches. The pendulum movement can include not only a swinging in an approximately horizontal direction but also a turning or torsional swinging in an approximately vertical direction. Both the cable winch for the actuating cable and the cable winch for the retaining cable can be controlled by the control device in such a way that a pendulum movement of the cable-suspended cable gripper is counteracted. This promotes occupational safety.

According to a development of the invention, it is advantageous for the control device to automatically control a movement of the cable gripper into the floor slot and/or a retraction of the cable gripper from the floor slot. In principle, the diaphragm wall grab can also be retracted and extended automatically become. The increasing depth of the slot can also be taken into account. The machine operator preferably has the possibility at any time to carry out these method steps or other method steps himself by directly intervening in the control device. In particular, when driving the diaphragm wall grab into a slot in the ground, this can be done under the direct control of the machine operator. A program step can be executed beforehand by the control device, which calms the movement of the cable gripper around a vertical axis (twisting) and transversely to the vertical axis (swinging) immediately before entering the created slot.

Furthermore, it is preferred that the control device is connected to the first cable winch and the second cable winch and controls them. In this way, coordinated actuation can take place on the holding and actuating cable in order to limit or completely avoid undesirable rotary and pendulum movements of the cable gripper.

According to a development of the invention, a particularly expedient operation of the gripper device results from the fact that a sensor device is provided with which a pendulum movement of the cable gripper is detected when the superstructure is rotated. The sensor device can be camera-based or have other contact-based or contactless sensors with which a pendulum movement transverse to the vertical and/or a twisting pendulum movement about a vertical axis can be detected. The movement data recorded in this way can be used by the control device in particular to control one or both cable winches in order to counteract the undesired or excessive oscillating movement.

For efficient gripper operation, it is advantageous according to a further embodiment of the invention that the control device opens the gripper scoops at the emptying position at a time when the oscillating cable gripper is still in a deflected position on the vertical position. Overall, this leads to an acceleration of the overall process. In addition, the pendulum movement can be counteracted by the targeted emptying of the rope gripper in a deflected position, since the resulting reduction in the pendulum mass has a calming effect on the pendulum movement.

A further efficient process sequence can also be achieved in that the oscillating cable gripper is moved into the floor slot by the control device, with the oscillating movement being calmed by contact with the floor. Once the pendulum movement has been reduced to a certain extent, the pendulum movement can be completely calmed down by specifically inserting the cable gripper into the slot in the floor.

With regard to the gripper device according to the invention, the invention is characterized in that a control device is provided which is designed to automatically rotate the upper carriage to an emptying position and open the gripper shovels to discharge soil material and/or rotate the upper carriage from the emptying position back to the floor slot to control. The advantages described above can be achieved in this way.

In the case of the gripper device according to the invention, it is particularly preferred that it is designed to carry out the method according to the invention described above.

Furthermore, in one embodiment of the gripper device according to the invention, it is preferred that a first detection device for detection of a first cable force on the retaining cable and a second detection device for detection of a second cable force on the actuating cable are provided, and that the control device with the first detection device, the second detection device of the first cable winch and the second cable winch and is designed to control the first cable winch and/or the second cable winch according to a control program specification depending on the detected first cable force on the retaining cable and the detected second cable force on the actuating cable.

One aspect of the invention is based on the knowledge that a torque on a cable gripper about its longitudinal axis depends on the cable forces in the tether and the actuating cable. Detection devices are provided with which a cable force on the retaining cable and a cable force on the actuating cable are detected. The force values recorded in each case can be fed to a control device which has a first cable winch for the retaining cable and a second cable winch for the actuating cable in accordance with inputs and specifications by the machine operator controls. With the control device, the forces in the retaining cable and in the actuating cable can be matched to one another via a corresponding control of the respective cable winch (winding/unwinding), so that with a given or desired rotational position of the cable gripper, no torque about the longitudinal axis through the cable gripper can be exerted on it Tether and the actuating cable are generated. In principle, the control device can also be used to generate a defined, variable torque for a desired rotation by influencing the respective cable forces accordingly. A pendulum movement can thus be counteracted.

A preferred embodiment of the invention consists in that a defined ratio between the first cable force in the retaining cable and the second cable force in the actuating cable can be specified and adjusted by the control program specification of the control device. The same or different configurations of retaining cable and actuating cable can be taken into account in the control program specification. With a preferably identical design of the retaining cable and the actuating cable, but with opposite cable lay, a torque compensation can be achieved by setting largely the same tensile forces in the cables. If the cables are designed differently with regard to a different cable structure, this can be taken into account and preset accordingly in the control program specification. When specifying the control program, additional geometric conditions on the cable gripper, for example with regard to different attachment points of the cables on the gripper frame, can also be preset and taken into account.

A further preferred embodiment of the invention is that the control device is designed with a compensation mode in which the cable winches are controlled in such a way that the first cable force on the retaining cable and the second cable force on the actuating cable are matched to one another. In particular, the cable winches can be controlled in such a way that the torques in the actuating cable and the retaining cable compensate or weaken one another. In this way, the rotational position of the cable gripper about its longitudinal axis can be stabilized. Undesirable rotation of the cable gripper about its longitudinal axis during operation can thus be largely avoided.

In particular, according to a development of the invention, it is advantageous that the control device is designed with a twisting mode in which the cable winches are controlled in such a way that a targeted twisting of the cable gripper about a vertical longitudinal axis can be generated. Starting from a stable rotational position, a desired change in the rotational position can be brought about by a machine operator. The control device can also be designed so that a value or a measure for a desired rotation is specified by the machine operator via an input device, the winches being actuated by the control device according to the program logic in such a way that the desired changed rotational position is set.

A further preferred embodiment of the invention is that the control device is designed with a mode for opening and/or closing the grab scoops at a predetermined height. This means that when opening and/or closing, the two cable winches can be adjusted to one another in such a way that the lowest point of the gripper scoops preferably remains at the same height or a specific change in height is achieved. For example, when closing, it can be controlled whether the teeth or tooth tips of the grab shovels move on a circular path or a straight path or a defined path curve in between. This can be adjustable in particular depending on the type of soil.

The gripper can preferably be held hanging freely with closed gripper scoops on the actuating cable and retaining cable, with the cable force in the actuating cable and retaining cable being approximately the same, for example corresponding to approximately +/-1 t. Triggered by a control command from the device driver, the winch on which the operating cable is wound is automatically actuated in the direction of unwinding, which occurs either in free fall or with a force fit. At the same time, the winch on which the tether is wound is automatically actuated in the direction of winding. As a result, a carriage moves up in the grab body and opens the grab shovels via the push rods. A controlled relationship between the unwinding of the actuating cable and the winding up of the retaining cable can be achieved in that a vertical movement of the grab body against the subgrade or the ground during opening is avoided or minimized. Otherwise, without this control, the grab body would move down significantly when the grab buckets open.

Correspondingly, the control device can be designed with a mode for closing the grab shovels. This means that when opening and/or closing, the two cable winches can be matched to one another in such a way that the lowest point of the grab scoops preferably remains at the same height. Accordingly, when closing, it can be controlled whether the teeth or tooth tips of the grab scoops move on a circular path or a straight path or a path curve in between, which can be adjusted in particular depending on the type of soil.

The gripper can preferably be held hanging freely with the gripper scoop open on the actuating cable and retaining cable, with the cable force in the retaining cable almost corresponding to the entire gripper weight and the cable force in the actuating cable correspondingly being in the range of approx. 1 t to 2 t. Triggered by a control command from the device operator, the winch on which the operating cable is wound is automatically actuated in the winding direction and at the same time the winch on which the retaining cable is wound is automatically actuated in the unwinding direction either in free fall or with a force fit. As a result, the carriage moves down in the grab body and closes the grab bucket via the push rods.

A controlled ratio of winding-up of the closing rope and unwinding of the tether can be achieved in preventing or minimizing vertical movement of the grapple body against the subgrade or soil during closure. Without this control, the grapple body would otherwise move significantly upwards when the grapple buckets close

A further preferred embodiment of the invention consists in that the control device is designed with a mode for automatically opening and then immediately closing the gripper shovels.

The gripper can preferably be held hanging freely with the closed, filled gripper shovel on the actuating cable and retaining cable, with the cable force in the actuating cable and retaining cable being approximately the same, in particular approximately +/-1 t.

When the operator operates a control element, the processes of opening and closing the grab shovels are automatically carried out in one sequence. The aim here is to do this in the shortest possible time to be carried out, since the cable force in the retaining cable is significantly higher than in the actuating cable for the "grab shovel open" status. This can lead to twisting of the gripper around the longitudinal axis. In order to counteract this twisting, a rotary impulse can be applied in the opposite direction before the automatic opening/closing is carried out, in particular by means of an automatic, targeted short-term increase in the cable force in the actuating cable.

A further preferred embodiment of the invention is that the control device can detect the degree of opening of the grab shovels and this is visualized for the operator.

By detecting the ratio of the depth or unwinding length of the retaining cable and the actuating cable, it is possible to determine the degree of opening of the grab shovel via the device control and in particular to visualize it on a screen for an operator. This can be done by displaying a numerical value, such as an opening degree of 50%, and/or a graphic display, such as displaying the grab buckets with an opening angle or as a bar graph. Without this display, the opening degree of the shovels and thus the status of the grab in the slot are not visible to the operator.

According to a development of the invention, it is preferred that at least one third detection device is provided for detecting a rotational position of the cable gripper and/or a change in the rotational position. This can be done by an optical detection device, a rotary encoder, a gyroscope on the cable gripper or in any other suitable way. In this way, feedback on the rotational position or the rotation of the gripper can take place when it is activated by the control device, so that the rotational position or the rotation can be regulated. This enables a particularly precise adjustment of the rotational position of the cable gripper.

A further improvement in operability results according to a further embodiment of the invention in that at least one further detection device is provided, in particular for detecting a vertical position of the cable gripper, a distance and/or an angular position of the cable gripper from the carrier device. The additional parameters recorded in this way can be used by a machine operator are displayed immediately and/or processed by the control device for controlling the gripper.

A further advantageous embodiment of the invention consists in that a control panel for a manual control for actuating the cable gripper and/or the cable winch is provided. The control panel as an input device is designed in particular in such a way that a machine operator enters a desired rotation or movement of the cable gripper, for example as a numerical value or angle, preferably using appropriate control elements such as a cursor, a rotary knob, switches or buttons, in particular in combination with a screen. The machine operator therefore no longer has to enter the winches and a rotation of the winches directly. Rather, according to the operator input for the position of the gripper via the control device with the program logic, the machine with the individual motors and actuators is controlled in such a way that the desired position is set largely without undesired twisting.

According to one embodiment variant of the invention, it is particularly preferred that the control device is designed with an automatic program, by means of which the cable gripper can be automatically moved to an emptying position and/or to a removal point. An automatic program can be permanently stored or can be individually defined and saved by a machine operator in the case of repetitive processes. In this way, larger movement sequences of the gripper can be carried out automatically, in particular a movement to the emptying position and/or back to a removal point. Such traversing paths of the cable gripper occur with a high frequency of repetition, in particular when creating deep slots in the ground.

In principle, the individual cables can be of the same or different design. According to one embodiment of the invention, it is particularly advantageous that the retaining cable on the first cable winch has a first winding which is opposite to a second winding of the actuating cable on the second cable winch. In particular, the retaining cable and the actuating cable have a direction of lay that is opposite to one another, or a so-called cable lay. When a tensile force is applied, opposing torques result on the ropes. This makes it easier to compensate for the torques for stabilizing the position of the cable gripper during operation.

According to a further embodiment of the invention, it is particularly advantageous that a display screen is provided for the control device for operation. The display screen can in particular be designed as a touch screen, on which at least some of the operating elements for a machine operator are implemented. Furthermore, a position of the cable gripper can be displayed in different representations on the display screen in order to further facilitate operation for a machine operator.

The gripper device can be used in particular for different tasks. A preferred variant of the method is that the ground is removed by means of the cable gripper and, in particular, a slot is created in the ground. The rope gripper can be designed in particular as a so-called diaphragm wall gripper, with which a slot for a sealing and/or retaining wall in the ground, for example for enclosing an excavation pit, can be created.

Fig. 1

eine perspektivische Ansicht einer erfindungsgemäßen Greifervorrichtung;

Fig. 2

eine Vorderansicht des Seilgreifers der Greifervorrichtung von Fig. 1 mit geschlossenen Greiferschaufeln; und

Fig.3

eine Vorderansicht des Seilgreifers entsprechend Fig. 2 mit geöffneten Greiferschaufeln.

The invention is described in more detail below using a preferred exemplary embodiment, which is illustrated schematically in the drawings. In the drawings show:

1

a perspective view of a gripper device according to the invention;

2

a front view of the cable gripper of the gripping device of FIG 1 with closed grapple buckets; and

Fig.3

a front view of the rope gripper accordingly 2 with open grapple buckets.

A gripper device 10 according to the invention 1 has a mobile carrier device 12 with a crawler chassis as an undercarriage 14 . An upper carriage 16 with an operator's cabin 17 is rotatably mounted on the undercarriage 14 about a vertical axis of rotation. A control device including an input device for a machine operator is located inside the operator's cab 17 .

A cantilever arm 18 is articulated on the superstructure 16 so as to be pivotable about a horizontal axis. A tether 24 is guided on a head 20 of the cantilever arm 18 with deflection pulleys, at the end of which a cable gripper 30 with a gripper frame 32 and lower gripper blades 34 is attached. The tether 24 for raising and lowering the cable gripper 30 can be actuated via a first cable winch 21 on the carrier device 12 . Also located on the carrier device 12 is a second cable winch 22 for an actuating cable 44, which is also guided over the head 20 to the cable gripper 30 for actuating the gripper scoops 34 at the lower end of the gripper frame 32.

The functioning of the gripper device 10 according to the invention is described below in connection with the figures 2 and 3 explained in more detail.

In a central area of the gripper frame 32, an actuating carriage 42 of an actuating device 40 for actuating the gripper scoops 34 is mounted so that it can be displaced in a vertical longitudinal direction. The end of the retaining cable 24 is attached to the upper end of the actuating carriage 42 so that the cable gripper 30 is held by the actuating carriage 42 .

A linkage mechanism 46 with linkage rods 47 is arranged at a lower end of the actuating carriage 42 . The connecting rods 47 are connected in an articulated manner to the actuating carriage 42 on the one hand and to one of the gripper shovels 34 on the other hand. The gripper shovels 34 are themselves mounted pivotably on the lower end of the gripper frame 32 via pivot bearings 35 . The gripper scoops 34 can be opened and closed by a relative displacement of the actuating carriage 42 in relation to the gripper frame 32 . A relative upward displacement of the actuating carriage 42 pulls the connecting rods 47 upwards, whereby the grab shovels 34 are pivoted about their pivot axes 35 into their open position, which is illustrated in FIG 3 is shown.

A pulley arrangement 50 for the actuating cable 44 is provided below the actuating carriage 42 . The pulley arrangement 50 has at least one upper roller 52, which is rotatably mounted on the actuating carriage 42, and at least one lower roller 54, which is rotatably mounted on a lower region of the gripper frame 32. The rollers 52, 54 are fed from above by the actuating cable 44 forming loops 56 or trains looped, the lower end of the actuating cable 44 is firmly connected to the gripper frame 32. The actuating carriage 42 is thus adjustably connected or coupled to the gripper frame 32 via the actuating cable 44 .

Starting from the open position according to 3 by pulling the actuating cable 44 upwards through the second cable winch 22, the actuating carriage 42 is pulled downwards by the pulley arrangement 50 relative to the gripper frame 32. The connecting rods 47 press the gripper scoops 34 downwards with an increased closing force, the gripper scoops 34 about their pivot bearing 35 in the closed position according to FIG 2 be pivoted.

When used in a slot in the ground, ground material can be gripped and enclosed between the gripper shovels 34 with a closing force that is increased compared to the tensile force on the actuating cable 44 .

After pulling the cable grab 30 out of a slot in the ground and moving to a dump position, the pulling force on the actuating cable 44 may be reduced. In this way, the gripper frame 32 moves downwards relative to the actuating carriage 42 due to its weight, so that the gripper shovels 34 are pivoted back into their open position via the connecting rods 47, as in FIG 3 is shown.

This described arrangement is only exemplary. In principle, other block and tackle arrangements with different cable linkages and a different linkage mechanism can also be selected, which allow comparable gripper shovel actuation.

When the gripper buckets 34 are full, the superstructure 16 is removed from the in 1 The position shown is automatically pivoted by 90 degrees around the vertical axis to an emptying position. The cantilever arm 18 can also be adjusted here. At the emptying position, the grab buckets 34 are opened to discharge the soil material, even if the cable grab 30 is still performing an oscillating movement. The cable gripper 30 can also be rotated about its longitudinal axis in order to align it with the trough of a truck. The superstructure 16 can then automatically return to the position according to FIG 1 be swung back.

From there, the cable gripper 30 is lowered into the ground into a slot in order to take up new soil material when the gripper blades 34 are open. A retraction then occurs with the gripper buckets 34 closed to the position after 1 and another emptying process.

When the cable gripper 30 is actuated, the forces and movements between the retaining cable 24 and the actuating cable 44 must be coordinated in order to increase the torques in the individual cables and thus the torques of the attached cable gripper 30 about its longitudinal axis, in particular due to a so-called lay direction in the case of coiled cables steer.

According to the invention, forces in the retaining cable 24 and the actuating cable 44 are detected via corresponding detection devices, which can be arranged, for example, on the cable winches 21, 22 or on the deflection rollers at the head 20 of the cantilever arm 18. Via a control device, which is preferably arranged in the operator's cabin 17 on the carrier device 12, the winches 21, 22 can be controlled depending on the detected cable forces in such a way that either the pendulum movement to the longitudinal axis or the rotational position of the cable gripper 30 about its longitudinal axis is stabilized or a targeted torsion desired by the machine operator is achieved. The machine operator can make corresponding inputs into the control device for a desired automatic movement, a compensation mode for position stabilization or inputs for a desired rotational position of the steep gripper 30 . Based on this, the control device of the superstructure 16 can control the extension arm 18 or the cable winches 21, 22 accordingly in order to bring about the desired positioning and opening/closing of the cable gripper 30. This simplifies and facilitates the control of a simply constructed cable gripper 30 to a considerable extent for a machine operator.

Claims (15)

Method for operating a gripper device with a carrier device (12) and a cable gripper (30) arranged thereon, which - a gripper frame (32) which is held on the carrier device (12) via a retaining cable (24), - at least two grab scoops (34) which are pivotally mounted at a lower end of the grab frame (32) between a closed position and an open position, and - has an actuating device (40) with an actuating cable (44) for pivoting the grab shovels (34), - wherein an actuating cable (44) is guided from the carrier device (12) to the actuating device (40) and - the carrier device (12) has a driven first cable winch (21) for the retaining cable (24) and a driven second cable winch (22) for the actuating cable (44), - wherein the carrier device (12) has an undercarriage (14) and an upper carriage (16) rotatably mounted thereon about a vertical axis and having a cantilever arm (18) on which the cable gripper (3) is mounted in a vertically adjustable manner, wherein - to form a slot in the ground, the cable gripper (30) with open gripper scoops (34) is lowered into the ground by means of the retaining cable (24) in a removal step, - the grab shovels (34) are closed to remove and pick up soil material, - Pull the cable gripper (30) out of the ground using the retaining cable (24) and/or the actuating cable (44) and close it by twisting the superstructure (16). is pivoted to an emptying position, at which the grab scoops (34) are opened to discharge the picked-up soil material, and - then the cable gripper (30) is moved back into the bottom slot to repeat the removal step, characterized,
that a control device is provided with which a rotation of the superstructure (16) to the emptying position and an opening and closing of the gripper shovels (34) to discharge the soil material and/or a rotation of the superstructure (16) from the emptying position back to the bottom slot are automatically controlled . Method according to claim 1, characterized, that the gripper scoops (34) are opened by the control device while the cable gripper (30) is still in a pendulum movement due to the twisting of the superstructure (16). Method according to claim 1 or 2, characterized, that the control device automatically controls insertion of the cable gripper (30) into the floor slot and/or retraction of the cable gripper (30) from the floor slot. A method according to any one of claims 1 to 3 characterized, that the control device is connected to the first cable winch (21) and the second cable winch (22) and controls them. A method according to any one of claims 2 to 4 characterized, that a sensor device is provided with which a pendulum movement of the cable gripper (30) when the superstructure (16) is rotated is detected. A method according to any one of claims 2 to 5 characterized, that the gripper scoops (34) are opened by the control device at the position at a point in time at which the oscillating cable gripper (30) is still in a position deflected from a vertical position. A method according to any one of claims 2 to 6 characterized, that the oscillating cable gripper (30) is moved into the floor slot by the control device, the oscillating movement being calmed by contact with the floor. Gripper device with a carrier device (12) and a cable gripper (30) arranged thereon, which - a gripper frame (32) which is held on the carrier device (12) via a retaining cable (24), - at least two grab scoops (34) which are pivotally mounted at a lower end of the grab frame (32) between a closed position and an open position, and - has an actuating device (40) with an actuating cable (44) for pivoting the grab shovels (34), - wherein an actuating cable (44) is guided from the carrier device (12) to the actuating device (40) and - the carrier device (12) has a driven first cable winch (21) for the retaining cable (24) and a driven second cable winch (22) for the actuating cable (44), - the carrier device (12) having an undercarriage (14) and an upper carriage (16) mounted thereon so that it can rotate about a vertical axis and having a cantilever arm (18) on which the cable gripper (30) is suspended in a vertically adjustable manner, characterized,
that a control device is provided which is designed to rotate the superstructure (16) to an emptying position and to open and close the automatically control gripper shovels (34) for discharging soil material and/or rotating the superstructure (16) from the emptying position back to the bottom slot, with the gripper shovels (34) preferably opening and closing automatically. Gripper device according to claim 8, characterized, that this is designed to carry out the method according to one of claims 1 to 7. Gripper device according to claim 8 or 9,
characterized, - that a first detection device for detecting a first cable force on the retaining cable (24) and a second detection device for detecting a second cable force on the actuating cable (44) are provided, - that the control device is connected to the first detection device, the second detection device, the first cable winch (21) and the second cable winch (22) and is designed depending on the detected first cable force on the retaining cable (24) and the detected second cable force to control the first cable winch (21) and/or the second cable winch (22) on the actuating cable (44) according to a control program specification. Gripper device according to claim 8 to 10, characterized, that the control device is designed with a compensation mode in which the cable winches (21, 22) are controlled in such a way that the first cable force on the retaining cable (24) and the cable force on the actuating cable (44) are matched to one another. Gripper device according to one of claims 8 to 11, characterized, that the control device is designed with a twisting mode in which the cable winches (21, 22) are controlled in such a way that a targeted twisting of the cable gripper (30) about a vertical longitudinal axis can be generated. Gripper device according to one of claims 8 to 12, characterized, that at least one third detection device is provided for detecting a rotational position of the cable gripper (30) and/or a change in the rotational position. Gripper device according to one of claims 1 to 13, characterized, that at least one further detection device is provided, in particular for detecting a vertical position of the cable gripper (30), a distance and/or an angular position of the cable gripper (30) from the carrier device (12). Gripper device according to one of claims 8 to 14, characterized, that the tether (24) on the first cable winch (21) has a first direction of lay which is opposite to a second direction of lay of the actuating cable (44) on the second cable winch (22).

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