Rope gripper and method for operating a rope gripper

Abstract

The invention relates to a rope grab with a grab frame, at least two grab blades which are adjustably mounted at a lower end of the grab frame between a closed position and an open position, a retaining rope for holding the rope grab, and an actuating device with an actuating rope for actuating the grab blades. According to the invention, at least one actuating element is adjustably mounted on the rope grab, which can be adjusted between different positions by means of a power-driven actuator.

Description

[0001] The invention relates to a rope grab with a grab frame, at least two grab blades which are adjustable at a lower end of the grab frame between a closed position and an open position, a retaining rope for holding the rope grab and an actuating device with an actuating rope for actuating the grab blades, according to the preamble of claim 1.

[0002] The invention further relates to a method for operating a rope grab or a grab device, according to the preamble of claim 16.

[0003] Grab devices are used in specialist foundation engineering to create trenches in the ground. Diaphragm walls can then be constructed in these trenches to support and / or seal excavation pits.

[0004] Grab devices essentially comprise a grab with grab buckets, the grab suspended from a carrier device, typically a boom crane, by a tether cable. The tether cable allows the grab to be lowered into the ground. By closing the grab buckets, soil material can be excavated and collected in the grab. The grab is then pulled back out of the ground by the tether cable and swung by the carrier device to a discharge position, where the grab buckets are opened to release the soil material. The grab is then swung back into its working position and inserted into the trench in the ground for another grab operation.

[0005] There are two different types of grippers used on such gripping devices: hydraulic grippers and cable grippers. A so-called hydraulic gripper is known, for example, from EP 3 798 367 A1. In a hydraulic gripper, the movement for opening and closing the gripper blades is generated by a hydraulic cylinder located on the gripper frame.

[0006] These types of hydraulic grabs are relatively easy to operate and control thanks to the hydraulic system. The existing hydraulic supply allows for the integration of extendable control flaps on the grab frame, which are hydraulically actuated. These controllable and hydraulically adjustable flaps allow the grab's position within the trench to be set and, if necessary, corrected. This enables the creation of highly reliable and precisely positioned vertical diaphragm walls in the ground.

[0007] However, hydraulic lines are required for the supply and return of hydraulic fluid, running parallel to the support cable. The carrier unit must be equipped with appropriate hose reels for the hydraulic lines, along with corresponding winch drives and a suitably designed hydraulic system. This increases the size and cost of the gripper device.

[0008] In contrast, so-called cable grabs offer a significantly simplified design. Such a generic cable grab is known, for example, from EP 4 134 489 A1 or EP 4 134 490 A1. In a cable grab, the opening and closing movement of the grab buckets is effected by an actuating cable. The actuating cable runs essentially parallel to the retaining cable from the actuating device of the grab buckets to the carrier device. By means of a separate winch for the actuating cable, the grab buckets can be opened or closed by unwinding or winding the actuating cable onto the winch.

[0009] With a cable grab, the complex hydraulic lines leading to the grab are eliminated. Only an additional operating cable with a corresponding winch is required. Such an operating cable also requires significantly less maintenance than hydraulic lines and a corresponding hydraulic system.

[0010] However, operating and controlling the position of a rope grab is not as straightforward as with a hydraulic grab and requires an experienced machine operator. In particular, the lack of a hydraulic supply to the grab prevents the use of hydraulically controlled control flaps. A degree of change, and thus control, of the rope grab's position can be achieved by the operator adjusting the suspension point of the support rope, for example, by moving the boom crane. This can exert certain tilting moments on the rope grab, thereby altering its position and / or orientation within the slot. Such position control, however, demands considerable skill and experience from the operator and does not provide the same level of precise control as with control flaps.

[0011] Because of the desired simple design of a rope grab, which is basically only connected to a carrier device via carrying and operating ropes, practically no sensors with data acquisition or other electrical components can be used on the rope grab, especially when used in the ground, because there is no power supply.

[0012] The invention is based on the Task The basis is to specify a rope grab and a method for operating the rope grab, in which furthermore a simple construction and in particular a simple suspension of the rope grab and at the same time a simple operability of the rope grab in the ground is given.

[0013] The problem is solved, firstly, by a rope gripper with the features of claim 1 and, secondly, by a method with the features of claim 16. Preferred embodiments of the invention are specified in the respective dependent claims.

[0014] The rope gripper according to the invention is characterized in that at least one actuating element is adjustable on the rope gripper, which can be adjusted between different positioning positions by means of an energy-driven actuator.

[0015] A fundamental aspect of the invention is to arrange one or more actuating elements on the cable grab itself, which can be adjusted by means of an energy-driven mechanism. This allows for additional functionalities on the cable grab, such as actuating elements for position control or for assisting the opening or closing of the grab buckets. An actuating element is essentially an adjustable component that can assume defined different positions by means of an actuator. The at least one energy-driven actuator can be located directly on the cable grab or separately, for example, on a carrier device. This allows for continuous or discontinuous adjustment or actuation of the at least one actuating element, for example, when the cable grab is pulled out of the ground and is located close to the carrier device.The rope grab can be equipped with a self-sufficient power supply, such as a battery or a pressure accumulator, so that no power line needs to be routed to the rope grab.

[0016] According to a further development of the invention, it is preferred that at least one actuating element is designed with a control flap or a control frame, which is adjustably arranged on the grab for controlling the position of the rope grab in a slot in the ground. Such control flaps are known and frequently used in conventional hydraulic grabs. By extending or retracting control flaps on the grab frame, the position and orientation of the rope grab relative to the vertical in the slot in the ground can be influenced and preferably precisely adjusted. With the arrangement according to the invention, this function can now also be implemented in rope grabs, thereby significantly simplifying and improving the functionality of a rope grab and, in particular, its position control in the ground.

[0017] This allows a cable grab to be controlled in a similar way to a hydraulic grab by means of controllable actuators for positional alignment, without the need for complex hydraulic lines to the cable grab and large cable reels mounted on the carrier vehicle. The control unit for actuating the at least one actuator can be located on the cable grab itself or remotely on the ground surface, particularly on a carrier vehicle.

[0018] Another preferred embodiment of the invention consists in at least one actuating element being designed to exert, and in particular increase, a force for opening and / or closing the grab buckets. This allows, particularly in certain operating situations, such as when encountering a rock, a force to be exerted via the actuating element, preferably in addition to the force exerted by the actuating device, to open or, in particular, close the grab buckets. This increases the usability of the cable grab.

[0019] Particularly according to a further development of the invention, it is advantageous that the at least one actuating element for exerting a force to open and / or close the gripper blades comprises an actuating cylinder, in particular a hydraulic cylinder, which is configured to exert a force from the gripper frame to the positioning carriage or vice versa. By arranging one or more actuating cylinders, an additional actuating force can be exerted for the relative displacement of the gripper frame and positioning carriage, so that a greater force can be exerted via the actuating device to open or close the gripper blades. The actuating cylinder can in particular be a hydraulic cylinder, so that a noticeable additional force can be transmitted to the gripper blades in addition to the force exerted by the actuating cable.

[0020] The control of the at least one actuator can be performed, for example, by the carrier device or by a control unit on the rope grab itself. The control unit on the rope grab can preferably be connected to one or more sensors for detecting the position of the rope grab, such as at least one tilt sensor. It is also advantageous to detect the depth of the rope grab via a sensor; this can be achieved, for example, by a pressure sensor arranged on the rope grab. Depending on the detected position data, the control unit can autonomously actuate the at least one actuator according to a stored control logic (control program) to achieve a desired position and / or orientation. It is also possible for the control unit to display to an operator how to adjust the actuators so that the grab is positioned as desired the next time it enters the slot.

[0021] For data transmission, a wireless or wired transmitter can preferably be arranged, which, with suitable design, can utilize at least one cable of the grab to the carrier device. Typically, the tethering cable and the operating cable are steel cables with metallic strands, which are generally suitable for transmitting electrical, electromagnetic, or acoustic signals. A radio transmitter, for example, can be used as the transmitter, which, depending on its transmission power, can send signals from a trench in the ground to the ground surface, or, if the grab is outside the trench (e.g., for emptying the filled grab buckets), to the carrier device, at least to a certain depth.

[0022] Advantageous embodiments of the invention lie in the fact that the at least one actuator is arranged on the rope grab or separately from it. With an independent power supply and an actuator arranged on the rope grab, adjustment can be performed during operation, even when the grab is in the ground, or only at specific times, for example, when the rope grab is located outside the ground and connected to an actuator separate from the grab. The actuator can be attached to the rope grab only at the time of adjustment of the actuating element, which is adjustable. This can be an attachable and detachable electric drive or an actuator held by an operator, such as a cordless screwdriver.

[0023] According to a further development of the invention, it is particularly advantageous that the at least one actuator is designed as an electric drive, in particular as an electric linear drive or as an electric motor, or as a drive operated with a pressure fluid, in particular a hydraulic motor or a hydraulic cylinder. The individual drives can perform independent functions on the cable gripper and / or serve, for example, to support the closing and / or opening movement of the gripper blades effected by the actuating cable.

[0024] A particularly advantageous embodiment of the rope gripper, according to one embodiment of the invention, is achieved by arranging an energy storage device, in particular an accumulator for electrical current and / or a pressure vessel for a pressure fluid, on the rope gripper, wherein the energy storage device is designed to supply the at least one actuator with energy. This ensures an independent energy supply to the rope gripper without the need for an additional power line to be routed to the rope gripper during operation.

[0025] According to a further development of the invention, it is particularly advantageous that an energy converter device is arranged on the rope gripper, which is capable of converting kinetic energy, which can be transmitted in particular from the holding rope and / or the actuating rope, into pressure energy and / or electrical energy.

[0026] This further development of the invention thus provides energy to the gripper by arranging an energy converter device on the rope gripper, which can convert the kinetic energy available at the rope gripper into pressure energy and / or electrical energy. This energy converter device can be designed in any way that allows the kinetic energy available at the rope gripper to be converted in the desired manner. In particular, the energy converter device can be designed to convert a movement of the holding rope and / or the actuating rope and / or an associated movement of the positioning carriage, a rotary movement on pulleys, or a vertical movement of the rope gripper as a whole into the required or desired pressure energy, in particular hydraulic energy or pneumatic energy, or into electrical energy.

[0027] In this way, a readily usable form of energy, in particular pressure energy and / or electrical energy, is available in sufficient quantity at the cable grab without the need for complex external supply lines from a carrier device. Sufficient energy supply directly at the cable grab makes it possible not only to arrange and use one or more energy-driven actuators, but also a wide variety of additional drives, sensors, or electronic control elements and components in virtually any configuration, which can simplify or even enable operation, control, and / or data acquisition.

[0028] In principle, the energy generated by the energy converter can be supplied directly to corresponding consumers on the rope grab. According to a preferred embodiment of the invention, it is advantageous that the energy generated by the energy converter can be stored, at least partially, in the energy storage device on the rope grab. Thus, the energy generated by the energy converter can be temporarily stored in the energy storage device. Additionally or alternatively, the energy storage device can also be charged externally with energy when the rope grab is located, for example, at ground level. The rope grab can be connected to a power supply line during a break in operation.This ensures a continuous energy supply to the rope grab, even if energy conversion at the rope grab is not uniform but only generated in certain operating situations, such as when closing and opening the grab buckets and / or when lifting or lowering.

[0029] In the generation and / or storage of electrical energy, one or more accumulators can be used. Appropriate electrical circuitry for storage can be installed, for example, with rectifiers, inverters, and / or transformers. Generated pressure energy can be transferred to a pressure accumulator, in particular a pressure vessel, for example, via a suitable piping system with control valves. Alternatively or additionally, energy can also be temporarily stored in a spring accumulator, for example, with a torsion spring, which can then drive, for example, a generator to produce electricity or a hydraulic pump when needed.

[0030] According to a further development of the invention, it is preferred that the energy conversion device has at least one pump cylinder with which a pressure fluid can be pressurized. In particular, the piston of a pump cylinder could be moved axially via one of the cables on the cable gripper, thus generating a pumping action. A pressure fluid provided in one or more corresponding containers on the cable gripper can thus be pressurized. The pressure fluid can be supplied directly to a consumer, such as an actuator cylinder, or temporarily stored in a pressure accumulator.

[0031] In a further development of the invention, it is particularly preferred that the pressure fluid is a liquid, especially hydraulic oil, or a gas, especially compressed air. Hydraulic oil is particularly well suited for pressure transmission. However, other liquids, especially water, can also be used. The use of water as the pressure fluid can be particularly advantageous when the gripper is used in sensitive environments, such as in a groundwater protection area. The same applies to the use of ambient air as compressed air.

[0032] A particularly advantageous embodiment of the rope grab is achieved according to one embodiment of the invention by providing an adjusting carriage which is adjustable relative to the grab frame by means of the actuating rope, a transmission device which converts a relative positioning movement between the base frame and the adjusting carriage into a movement for opening or closing the grab blades, and the adjusting carriage and / or the grab frame being connected to the energy conversion device for supplying kinetic energy. Such a base frame or grab frame and / or adjusting carriage can often be present on a rope grab for actuating the grab blades. Thus, the energy conversion device can be used relatively easily in existing rope grabs or implemented based on existing designs.In principle, a positioning slide, which is designed exclusively for actuating the energy converter device, in particular for actuating one or more pump cylinders, can also be arranged on the rope gripper.

[0033] Alternatively or additionally, energy conversion can also be achieved using at least one pulley on the rope grab, which is set in motion when the rope grab is opened and / or closed. The resulting rotation of the pulley can then drive, for example, an electric generator or a pump impeller (e.g., of a gear pump) to convert kinetic energy into electrical energy or pressure energy.

[0034] In general, the positioning carriage and the gripper frame can be coupled to each other in any suitable manner. According to one embodiment of the invention, it is particularly advantageous that the gripper frame and the positioning carriage are mounted so as to be displaceable relative to each other in a longitudinal direction of the gripper frame. In particular, the positioning carriage can be arranged centrally on the rope gripper, so that no or only minimal lateral forces act on the rope gripper during operation. This has a positive effect on the directional stability of the rope gripper. The retaining rope can be attached to the gripper frame or, preferably, to the positioning carriage, with the actuating rope effecting a relative displacement between the gripper frame and the positioning carriage.

[0035] According to a further embodiment of the invention, it is advantageous that, in addition to the at least one actuator for an actuating element, at least one further energy-driven consumer, in particular another actuator, a control unit, and / or a data acquisition device, are arranged on the rope gripper, which can be operated by energy converted by the energy converter device. The at least one actuator can be driven electrically or with a pressure fluid. This applies to both linear actuators, in particular actuator cylinders, and rotary actuators. The control and / or data acquisition devices can preferably be electrically operated. The data acquisition devices can comprise a wide variety of sensors, with the acquired data being temporarily stored either via a suitable transmitter to a carrier device or in a data storage device arranged on the rope gripper.

[0036] A preferred embodiment of the invention further comprises the fact that the pump cylinder can additionally be operated actively as an actuator cylinder, wherein pressurized fluid from a pressure vessel can be supplied to the pump cylinder. If required, this can be done via a suitable switching device, so that the pump cylinder is actively operated as an actuator cylinder, for example to support an opening or closing movement of the gripper blades.

[0037] A particularly advantageous embodiment of the invention lies in the arrangement of a control unit, especially on the rope grab, which is designed to control the position of the rope grab in a slot in the ground by actuating at least one actuator. If the control unit is arranged directly on the rope grab, it can be connected to position sensors and / or sensors for determining the depth of the rope grab in the slot, for example via a pressure sensor, and, depending on a stored control program, automatically actuate the at least one actuator to achieve a desired target position of the grab. If the control unit is arranged remotely from the rope grab, a corresponding transmitter and receiver can be provided for communication between the rope grab and the remote control unit.The external control unit can also be operated directly by a machine operator and / or by an automatic control program.

[0038] It is particularly preferred that at least one sensor for acquiring position data regarding the position of the cable grab is arranged on the cable grab and that the at least one sensor is in data communication with the control unit. This enables, for example, very precise position control in the ground.

[0039] According to a further advantageous embodiment of the invention, it is preferred that at least one pressure sensor is arranged on the rope gripper, which is connected to the control unit on the rope gripper. Based on a pressure signal from the at least one pressure sensor, the control unit can detect the depth of the rope gripper in the slot and actuate at least one actuator depending on a predetermined target depth. In particular, the control unit can contain control logic or a control program that sends a specific control command to an actuator when a predetermined target depth is reached. This allows a certain degree of automatic control of the rope gripper in a slot, even at greater slot depths, independent of external control. In particular, the control unit can thus extend actuators to fix the position of the rope gripper in the slot.This allows, for example, reliable and more efficient operation of the grab buckets and a particularly efficient excavation movement by the grab buckets.

[0040] The invention further comprises a gripping device with a carrier unit having a winch for a retaining cable and an actuating cable, wherein the gripping device is further developed according to the invention in that a cable gripper according to the invention is arranged on the carrier unit and held by the retaining cable. The advantages previously outlined for using such a gripping device can be achieved by using the cable gripper according to the invention as described above.

[0041] The grab device is preferably further developed by making the carrier device movable, in particular by having a crawler chassis. A superstructure can preferably be rotatably mounted on the crawler chassis. The cable grab can be lowered and raised via a mast or a boom arm, wherein a winch for the holding cable and a winch for the operating cable are arranged on the carrier device, in particular the superstructure, in a manner known in principle.

[0042] Finally, the invention also includes a method for operating a rope grab or grab device according to the invention, wherein the method provides that the at least one adjusting element is moved to control the position of the rope grab in a slot in the ground. In this way, the advantages described for the rope grab according to the invention can be achieved in operation.

[0043] An advantageous variant of the method consists of arranging an energy storage device on the rope gripper, which stores energy directly on the rope gripper for adjusting the at least one actuating element. The energy storage device preferably comprises a pressure vessel, a spring accumulator, and / or an electric current accumulator. This device can, in particular, store converted energy on the rope gripper. Thus, even with uneven energy conversion, for example, only during certain operating conditions, a consistent energy supply to the rope gripper for energy-driven components can be ensured.

[0044] Furthermore, according to one embodiment of the invention, it is preferred that an energy conversion device is arranged on the gripper frame, by which kinetic energy, which is transferred in particular from the retaining rope and / or the actuating rope to the rope gripper, is converted into pressure energy and / or electrical energy. In this way, kinetic energy can be transferred into another readily usable form of energy, which can be used directly to drive components on the rope gripper.

[0045] Finally, a preferred embodiment of the method according to the invention consists in creating a slot in the ground with the cable grab and, in particular, forming a foundation element in the ground therein. The foundation element can, in particular, be a cutoff wall segment for a cutoff wall or a retaining wall segment for a retaining wall.

[0046] According to the invention, a hybrid gripper can be created, so to speak, which combines the advantages of the simple construction and suspension of a rope gripper with the advantages of a hydraulic gripper, for example with regard to the possibility of targeted position control by means of adjustable control flaps.

[0047] The invention is further described below with reference to a preferred embodiment. The drawings show: Fig. 1 a perspective view of the basic structure of a gripper device according to the invention; Fig. 2 a front view of the rope gripper of the gripper device. Fig. 1 with closed grab buckets; Fig. 3 a front view of the rope grab accordingly Fig. 2 with open grab buckets; Fig. 4 a schematic front view of a rope grab according to the invention; and Fig. 5 a schematic representation of an energy converter device.

[0048] A gripper device 10 according to the invention Fig. 1 The mobile carrier unit 12 has a crawler chassis as its undercarriage 14. A superstructure 16 with an operator cabin 17 is rotatably mounted on the undercarriage 14 about a vertical axis of rotation. A control unit, including an input device for a machine operator, can be located inside the operator cabin 17.

[0049] A boom arm 18 is pivotally mounted on the superstructure 16 about a horizontal axis. A retaining cable 24 is guided on a head 20 of the boom arm 18, which has pulleys. A cable grab 30 with a grab frame 32 and lower grab buckets 34 is attached to the end of the cable. The retaining cable 24 can be actuated to raise and lower the cable grab 30 via a first winch 21 on the carrier unit 12. A second winch 22 is also located on the carrier unit 12 for an actuating cable 44, which is guided via the head 20 to the cable grab 30 for actuating the grab buckets 34 at the lower end of the grab frame 32.

[0050] 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.

[0051] In a central area of ​​the gripper frame 32, an adjusting carriage 42 of an actuating device 40 for actuating the gripper buckets 34 is mounted so as to be displaceable in a vertical longitudinal direction. The end of the retaining cable 24 is attached to the upper end of the adjusting carriage 42, so that the cable gripper 30 is held by the adjusting carriage 42.

[0052] At a lower end of the positioning carriage 42, a transmission device 45 with a linkage mechanism 46 and connecting rods 47 is arranged. The connecting rods 47 are pivotally connected at one end to the positioning carriage 42 and at the other end to one of the gripper blades 34. The gripper blades 34 are themselves pivotally mounted at the lower end of the gripper frame 32 via pivot bearings 35. By a relative displacement of the positioning carriage 42 with respect to the gripper frame 32, the gripper blades 34 can be opened and closed. By a relative displacement of the positioning carriage 42 upwards, the connecting rods 47 are pulled upwards, whereby the gripper blade 34 is pivoted about its pivot axes 35 into its open position, which is illustrated in Fig. 3 is shown.

[0053] Below the adjusting carriage 42, a pulley system 50 is provided for the actuating cable 44. The pulley system 50 has at least one upper pulley 52, which is rotatably mounted on the adjusting carriage 42, and at least one lower pulley 54, which is rotatably mounted on a lower portion of the gripper frame 32. The pulleys 52 and 54 are encircled by the actuating cable 44, which is supplied from above, forming loops 56 or pulleys. The lower end of the actuating cable 44 can be fixedly connected to the gripper frame 32. Alternatively, the lower end of the actuating cable 44 can also be fixedly connected to the adjusting carriage 42. The adjusting carriage 42 can thus be connected or coupled to the gripper frame 32 via the actuating cable 44 in a relatively adjustable manner.

[0054] Starting from the opening position according to Fig. 3By pulling the actuating cable 44 upwards, the second winch 22 pulls the adjusting slide 42 downwards relative to the gripper frame 32 via the pulley system 50. During this action, the connecting rods 47 press the gripper blades 34 downwards with an increased closing force, causing the gripper blades 34 to pivot about their pivot bearings 35 into the closed position. Fig. 2 be swerved.

[0055] When used in a slot in the ground, soil material can be gripped and enclosed between the grab buckets 34 by means of a closing force increased compared to the pulling force on the actuating rope 44.

[0056] After the cable grab 30 is pulled out of a slot in the floor and moved to an emptying position, the pulling force on the actuating cable 44 can be reduced. In this way, the grab frame 32 shifts downwards relative to the positioning carriage 42 due to its weight, so that the grab buckets 34 are swung back into their open position via the linkage rods 47, as shown in Fig. 3 is shown.

[0057] The described arrangement is only an example. In principle, other pulley systems with different rope linkages and linkage mechanisms can be chosen to enable comparable grab bucket operation.

[0058] According to Fig. 4A cable grab 30 according to the invention with actuating elements 80 is shown in detail. Several actuating elements 80 are arranged on the cable grab 30, each comprising a control flap 84 and an actuator 82. The control flaps 84 can be actuated by at least one actuator 82, in particular extended, retracted and / or positioned. This allows, in particular, one or more control flaps 84 to be controlled for the positional alignment of the cable grab 30 in the ground.

[0059] Furthermore, an energy converter device 60 can be arranged, which comprises a pump cylinder 62 with a cylinder housing 64, which is preferably fixedly attached to the gripper frame 32. A pump piston 66 projecting from the cylinder housing 64 is slidably mounted and can be connected at its free end to an adjusting slide 42.

[0060] The positioning carriage 42 and the gripper frame can, as previously described, preferably be moved relative to each other along the gripper frame 32 by means of the actuating cable 44, in order to open and close the gripper blades 34 via a transmission device 45 with a linkage mechanism 46. By moving the positioning carriage 42 relative to the gripper frame 32 by means of the actuating cable 44, the attached pump piston 66 is also axially adjusted, whereby the kinetic energy of the positioning carriage 42 can be converted into pressure energy by the pump cylinder 62.

[0061] A possible and preferred design of an energy converter device 60 and an arrangement for adjusting actuators 80 and / or 62 is shown schematically in Fig. 5 depicted accordingly. Fig. 4The energy converter device 60 can have a pump cylinder 62 with a cylinder housing 64 and a pump piston 66 slidably mounted therein. In this embodiment, the pump cylinder 62 is designed as a double-acting pump cylinder 62, which can discharge pressurized fluid, in particular hydraulic oil, to a pressure line 65 both during an extension movement and during a retraction movement of the pump piston 66 from or into the cylinder housing 64.

[0062] The pressurized fluid can be used in various ways, depending on the control via a control unit (not shown) using controllable valve units 69. For example, the pressurized fluid can be supplied to an energy storage device 70 with a pressure vessel 72, in which pressurized fluid can be stored. This fluid can then be released again as needed via a suitable switching device, for example, to actively operate the pump cylinder 62 as an actuator cylinder, and thus as an actuating element, such as to assist an opening or closing movement of the gripper blades 34.

[0063] Additionally or alternatively, the generated pressure fluid can also be used to drive a drive motor 67, in particular a hydraulic drive motor 67. A generator 68 can be operated via the drive motor 67 to generate electricity. The electricity generated in this way can be supplied directly to a consumer or to an accumulator 74 as part of an energy storage device 70. Electricity can be drawn from the accumulator 74 as needed.

[0064] Furthermore, one or more actuating elements can be operated via the pressurized fluid as an alternative or supplement, in particular by means of actuators 82 designed as hydraulic cylinders. The actuators 82 can preferably be used to control the control flaps 84 for controlling a basic orientation of the rope grab 30 in a slot in the ground.

Claims

1. Cable grab with - a grab frame (32), - at least two grab buckets (34) which are adjustable at a lower end of the grab frame (32) between a closed position and an open position, - a retaining cable (24) for holding the cable grab (30) and - an actuating device (40) with an actuating cable (44) for actuating the grab buckets (34), characterized by - that On the rope gripper (30) at least one actuating element (62, 80) is adjustable and can be adjusted between different positions by means of an energy-driven actuator (61, 82).

2. Rope gripper according to claim 1, characterized by that at least one actuating element (80) is designed with a control flap (84) or a control frame, which is adjustably arranged on the rope gripper (30) for controlling a position of the rope gripper (30) in a slot in the ground.

3. Rope gripper according to claim 1 or 2, characterized by that the energy supply of the at least one actuator (61, 82) is arranged on the rope gripper (30) or separately from it.

4. Rope gripper according to one of claims 1 to 3, characterized by that at least one actuating element (62) is designed to exert a force to open and / or close the gripper blades (34), in particular to increase it.

5. Rope gripper according to claim 4, characterized by that the at least one actuating element (62) for exerting a force to open and / or close the grab buckets (34) has an actuating cylinder, in particular a hydraulic cylinder, which is designed to exert a force from the grab frame (32) to the actuating slide (42) or vice versa.

6. Rope gripper according to one of claims 1 to 5, characterized by thatat least one actuator (82, 61) is designed as an electric drive, in particular an electric linear drive or an electric motor, or as a drive operated with a pressure fluid, in particular a hydraulic motor or a hydraulic cylinder.

7. Rope gripper according to one of claims 1 to 6, characterized by that An energy storage device (70), in particular an accumulator (74) for electric current and / or a pressure vessel (72) for a pressure fluid, is arranged on the rope gripper (30), wherein the energy storage device (70) is designed to supply energy to the at least one actuator (82, 61).

8. Rope gripper according to one of claims 1 to 7, characterized by thatAn energy converter device (60) is arranged on the rope gripper (30), with which a kinetic energy, which can be transmitted in particular from the holding rope (24) and / or the actuating rope (44), can be converted into pressure energy and / or electrical energy.

9. Rope gripper according to claim 8, characterized by that the energy generated by the energy converter (60) can be stored at least partially in the energy storage device (70) on the rope grab (30).

10. Rope gripper according to claim 8 or 9, characterized by that the energy converter device (60) has at least one pump cylinder (62) with which a pressure fluid can be pressurized.

11. Rope gripper according to one of claims 8 to 10, characterized by that a positioning slide (42) is arranged which is adjustable relative to the gripper frame (32) by means of the actuating cable (44), thata transmission device (45) is arranged with which a relative positioning movement between the gripper frame (32) and the positioning slide (42) can be transmitted into a movement for opening or closing the gripper blades (34), and that the positioning carriage (42) and / or the gripper frame (32) is connected to the energy converter device (60) for supplying kinetic energy.

12. Rope gripper according to one of claims 1 to 10, characterized by that a control unit, in particular on the rope grab (30), is arranged which is designed to control a position of the rope grab (30) in a slot in the ground by actuating the at least one actuating element (80).

13. Rope gripper according to claim 12, characterized by that at least one sensor for recording position data on the position of the rope gripper (30) is arranged on the rope gripper (30) and that at least one sensor is in data communication with the control unit.

14. Rope gripper according to claim 12 or 13, characterized by that at least one pressure sensor is arranged on the rope gripper (30), which is connected to the control unit on the rope gripper (30), wherein, based on a pressure signal from the at least one pressure sensor, the control unit can detect the depth of the rope gripper (30) in the slot and, depending on the detected depth, at least one actuating element (80, 62) can be actuated.

15. Gripper device with a carrier device (12) with a winch device for a holding rope (24) and an operating rope (44), characterized by that a rope gripper (30) according to one of claims 1 to 14 is arranged on the carrier device (12) and is held by the retaining rope (24).

16. Method for operating a rope grab (30) according to one of claims 1 to 14 or a grab device (10) according to claim 15, characterized by thatto control the position of the rope grab (30) in a slot in the ground by adjusting at least one adjusting element (80).

17. Method according to claim 16, characterized by that An energy storage device (70) is arranged on the rope gripper (30), with which energy for adjusting the at least one actuating element (80, 62) is stored directly on the rope gripper (30).

18. Method according to claim 16 or 17, characterized by that An energy converter device (60) is arranged on the rope gripper (30), by which kinetic energy, which is transmitted in particular by the holding rope (24) and / or the actuating rope (44), is converted into pressure energy and / or electrical energy.

19. Method according to any one of claims 16 to 18, characterized by that A slot is created in the ground using the cable grab (30), and in particular a foundation element is formed in the ground therein.

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