Grab apparatus, and method for operating a grab apparatus

Abstract

The invention relates to a grab apparatus comprising a carrier device and a cable grab which is mounted thereon and comprises: a grab frame which is held on the carrier device via a holding cable and can be lowered and raised via the holding cable (24); at least two grab buckets which are mounted at a lower end of the grab frame so as to be pivotable between a closed position and an open position; and an actuation device having an actuation cable for opening and closing the grab buckets, wherein an actuation cable is guided from the carrier device to the actuation device, the carrier device has a driven first cable winch for the holding cable and a driven second cable winch for the actuation cable, and a control device comprising an input unit is provided. According to the invention: in order to fill the grab buckets, a cycle count for opening and closing the grab buckets and / or for raising and lowering the cable grab can be input into the control device by means of the input unit; and the control device is designed to automatically repeat the opening and closing of the grab buckets and / or the raising and lowering of the cable grab according to the entered cycle count.

Description

[0001] GRIPPER DEVICE AND METHOD FOR OPERATING A GRIPPER DEVICE

[0002] The invention 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 holding cable and can be lowered and raised via the holding cable, at least two gripper blades which are mounted at a lower end of the gripper frame so as to be pivotable between a closed position and an open position, and an actuating device with an actuating cable for opening and closing the gripper blades, wherein the actuating cable is guided from the carrier device to the actuating device, the carrier device has a driven first cable winch for the holding cable and a driven second cable winch for the actuating cable and a control device with an input unit is arranged, according to the preamble of claim 1.

[0003] The invention further relates to a method for operating a gripper device with a cable gripper, which has a gripper frame which is held on a carrier device via a holding cable and can be lowered and raised via the holding cable, at least two gripper blades which are pivotally 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 opening and closing the gripper blades, wherein the actuating cable is guided from the carrier device to the actuating device, the carrier device has a driven first cable winch for the holding cable and a driven second cable winch for the actuating cable and a control device with an input unit is arranged, according to the preamble of claim 12. Gripper devices are used in special civil engineering for creating slots in the ground.Diaphragm walls can be constructed in the slits to support and / or seal excavations or for other purposes, such as walls or foundations.

[0004] Grabber devices primarily comprise a grab with grab buckets. The grab is suspended from a carrier device, typically a jib crane, via a tether. The tether allows the grab to be lowered into the ground. By closing the grab buckets, soil material can be removed and collected in the grab. The grab is then retracted from the ground via the tether and pivoted with the carrier device to an emptying position, where the grab buckets are opened to discharge the soil material. The grab is then pivoted back into its working position and inserted into the slot in the ground for another grabbing operation.

[0005] There are two different types of grippers used on such gripper devices: hydraulic grippers and rope 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 mounted on the gripper frame.

[0006] Such hydraulic grabs are relatively easy to operate and control thanks to the hydraulic system. However, the supply and discharge of hydraulic fluid requires appropriate hydraulic lines, which run parallel to the support cable. Appropriate cable reels for the hydraulic lines, with appropriate winch drives, and a suitably designed hydraulic system must be provided on the carrier device. This makes the grab device larger and more expensive. The hydraulic system also requires additional maintenance.

[0007] In contrast, so-called rope grabs offer a significantly simplified and therefore lighter design. One such rope grab is known, for example, from GB 2 126 981 A. In a rope grab, the opening and closing movement of the grab buckets is controlled 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. Using 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.

[0008] With a rope grab, the complex supply of hydraulic lines to the grab is eliminated. Only an additional operating cable with a corresponding winch is required. Such an operating cable is also considerably less maintenance-intensive than hydraulic lines with a corresponding hydraulic system.

[0009] However, operating a rope grab is not as easy as operating a hydraulic grab, requiring an experienced operator. One reason for this is that the use of rotating ropes, both for the holding rope and the actuating rope, can generate undesirable torques in various operating states, allowing the grab to rotate around its vertical axis.

[0010] Operating the rope grab requires relatively sensitive operation of the corresponding rope winches. This requires a certain amount of experience from the machine operator and also a high level of concentration during the process. Furthermore, the rope winches are often operated using foot pedals, making sensitive operation of the rope winches for several hours very strenuous for a machine operator.

[0011] Depending on the soil, after the opened grab buckets have been placed on the bottom of a slot and then closed, it may happen that the grab buckets are not sufficiently filled in certain soils, especially on harder soils.

[0012] The invention is based on the object of specifying a gripper device and a method for operating the gripper device, with which efficient gripper operation and simple operation are achieved.

[0013] The object is achieved, on the one hand, by a gripper device having the features of claim 1 and, on the other hand, by a method having the features of claim 12. Particular embodiments of the invention are specified in the respective dependent claims. The gripper device according to the invention is characterized in that, for filling the scoops, a cycle number for opening and closing the gripper scoops and / or for raising and lowering the rope gripper can be entered into the control device via the input unit, and in that the control device is designed to automatically repeatedly open and close the gripper scoops or repeatedly raise and lower the rope gripper in accordance with the entered cycle number.

[0014] To achieve the desired sufficient filling level of the grab buckets, the grab buckets can be opened and closed several times after being placed on a slot base or can be dropped several times onto the slot base in order to loosen sufficient soil material.

[0015] A basic idea of ​​the invention is to provide a machine operator with the ability to automatically open and close the grab buckets and / or lower and raise the grab to fill the buckets as required, with a desired number of cycles. A program is stored in the control unit, which then performs the processes multiple times according to the operator's input. This eliminates the need for laborious and strenuous repetitive operations by the machine operator. This significantly reduces the workload.

[0016] A preferred embodiment of the invention consists in that a first detection device is designed to detect the fill level of the grab buckets. The detection device, which is preferably connected to the control device, can thus indicate to a machine operator the extent to which the grab buckets are filled and whether, if applicable, a specified value for filling the grab buckets has been met or not. If a specified value for a minimum filling of the grab buckets with soil material is not reached, the automatic repeat function, i.e. the execution of a specific cycle number of actuation steps for filling the grab buckets, can be activated or triggered automatically by the control device or, in particular, by the machine operator.In principle, the first detection device for detecting the fill level of the grab buckets can be designed in any suitable manner, for example as an ultrasonic sensor, or it can comprise a camera system. According to a further development of the invention, it is particularly preferred for the first detection device to comprise at least one sensor for detecting a cable tensile force. The sensor is advantageously provided on the actuating cable, but could alternatively or additionally also be arranged on the retaining cable. The control device can determine the fill level of the grab buckets when the grab is pulled upwards based on the values ​​detected by the at least one sensor.

[0017] A further preferred embodiment of the invention is that at least one second detection device is designed to detect a vertical position of the cable grab. For this purpose, a sensor can be arranged on the holding cable and / or the actuating cable or on at least one of the cable winches. The second detection device is connected to the control device, by means of which a vertical distance of the grab blades from a slot or hole bottom can be determined. Thus, during repeated raising and lowering of the grab blades, a defined height from the hole bottom can be set via the control device during each work step for filling the grab blades, from which height the grab can then be lowered, in particular dropped, onto the hole bottom.The defined vertical distance between the hole bottom and the height for lowering / dropping the grab buckets can be determined and specified automatically by the control device or set by a machine operator.

[0018] According to a further development of the invention, it is advantageous that the control device is designed with a rotation mode in which the cable winches are controlled in such a way that a targeted rotation of the cable gripper about a vertical longitudinal axis can be generated. Starting in particular from a stable rotational position, a machine operator can bring about a desired change in the rotational position by appropriately actuating the cable winches, preferably via an input device such as a thumbwheel on a joystick. The control device can also be designed such that a value or a measure for a desired rotation is specified by the machine operator via an input device, wherein the control device actuates the winches in accordance with the program logic such that the desired changed rotational position is established.The rotational position is important for a diaphragm wall grab, as the grab frame is designed to guide the grab in the slot along the diaphragm walls. The cross-section of the grab frame is thus adapted to the slot cross-section, so there is little or no play and the grab can be inserted into the slot with high positioning accuracy.

[0019] A preferred embodiment of the invention is that at least one third detection device is configured to detect a rotational position of the rope gripper and / or a change in the rotational position. This can be achieved by an optical detection device, a rotary angle sensor, a gyroscope on the rope gripper, or in another suitable manner. Thus, feedback regarding the rotational position or rotation of the gripper can be provided when controlled by the control device, so that the rotational position or rotation can be regulated. This enables particularly precise adjustment of the rotational position of the rope gripper.

[0020] The invention is advantageously implemented in that the control device is designed to determine a specification for a cycle number and / or a lowering height and / or to suggest this to an operator depending on detected values ​​from at least one of the detection devices, in particular depending on a detected fill level. Based on values ​​stored in the control device, the control device can assess whether a cycle number and / or a lowering height set by the machine operator should be changed, for example, to achieve a higher fill level or to avoid unnecessary repeat processes. The lowering height is understood to be the height above the hole bottom from which the gripper is repeatedly lowered or dropped. This can preferably be between 0.2 m and three meters.Depending on a set cycle number and / or lowering height and the resulting filling of the grapple buckets, the control system can also determine the soil type, in particular whether the soil is hard or loose. Particularly in soils with varying soil layers, the specified cycle number or lowering height can be adjusted based on a depth profile, either automatically or based on a suggestion from the control system by the machine operator.

[0021] In principle, the actuating cable can be directly linked to the grab buckets. To achieve the highest possible closing forces, according to a further development of the invention, it is advantageous for the actuating device to have an actuating carriage connected to the grab buckets via a linkage mechanism, and for the actuating carriage to be displaceable along the grab frame for pivoting the grab buckets. The actuating carriage is preferably mounted on the grab frame so that it can be displaced in a longitudinal or vertical direction. The linkage mechanism can comprise joints, linkage rods, or linkage cables. An actuating carriage can, in particular, ensure the most uniform opening and closing movement of the grab buckets. This is advantageous for stabilizing the position of the rope grab.

[0022] Particularly high closing forces can preferably be achieved by providing a pulley assembly on the actuating carriage, with which an increase in force for closing the grab buckets can be generated. By means of a pulley assembly, the force on the actuating cable for closing the grab buckets can be multiplied depending on the number of pulls. The pulley assembly is positioned in particular between the actuating carriage and the lower end of the grab frame. The pulley assembly, which is mounted on the actuating carriage on the one hand and on the grab frame on the other, can be wrapped by the actuating cable, the lower end of which is attached to the grab frame or actuating carriage. This results in a corresponding extension of the cable path for actuating the actuating carriage with the desired increase in force.

[0023] 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 be designed, in particular, as a touchscreen on which at least some of the operating elements for a machine operator are implemented.

[0024] According to one embodiment of the invention, it is particularly preferred that the input unit comprises a control panel for an operator. Furthermore, it is advantageous that a display screen is provided for the control device. Using a control panel and / or a display screen, a machine operator can efficiently input and / or select the cycle number or the lowering height.

[0025] The method according to the invention is characterized in that a cycle number for opening and closing the grab buckets and / or for raising and lowering the rope grab is entered into the control device and that the grab buckets are automatically opened and closed repeatedly or the rope grab is raised and lowered repeatedly by the control device in accordance with the entered cycle number.

[0026] The method allows the previously described advantages to be achieved with the gripper device according to the invention. The method can be carried out in particular with the gripper device according to the invention, in particular as described above.

[0027] The grab device can be used for a variety of tasks. A preferred method variant involves removing soil using the rope grab, particularly to create a trench in the ground. The rope grab can be designed, in particular, as a so-called diaphragm wall grab, with which a trench can be created for a sealing and / or retaining wall in the ground, for example, for an excavation enclosure.

[0028] The invention will be further described below with reference to a preferred embodiment, which is schematically illustrated in the drawings. In the drawings:

[0029] Fig. 1 is a perspective view of a gripper device according to the invention;

[0030] Fig. 2 is a front view of the rope grab of the grab device of Fig. 1 with closed grab blades; and

[0031] Fig. 3 shows a front view of the rope grab according to Fig. 2 with the grab buckets open. A grab device 10 according to the invention according to Fig. 1 has a mobile carrier device 12 with a crawler track as the undercarriage 14. A superstructure 16 with an operator's cab 17 is mounted on the undercarriage 14, rotatable about a vertical axis of rotation. Located within the operator's cab 17 is a control device including an input device for a machine operator.

[0032] A boom arm 18 is pivotally mounted on the superstructure 16 about a horizontal axis. A holding cable 24 is guided on a head 20 of the boom arm 18 with deflection pulleys, to the end of which a rope grab 30 with a grab frame 32 and lower grab buckets 34 is attached. The holding cable 24 can be actuated to raise and lower the rope grab 30 via a first cable winch 21 on the carrier device 12. Furthermore, a second cable winch 22 for an actuating cable 44 is located on the carrier device 12, which is also guided via the head 20 to the rope grab 30 for actuating the grab buckets 34 at the lower end of the grab frame 32.

[0033] The functioning of the gripper device 10 according to the invention is explained in more detail below in connection with Figures 2 and 3.

[0034] In a central region of the gripper frame 32, an actuating carriage 42 of an actuating device 40 for actuating the gripper blades 34 is mounted so as to be displaceable in a vertical longitudinal direction. The end of the holding 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.

[0035] At a lower end of the actuating carriage 42, a linkage mechanism 46 with linkage rods 47 is arranged. The linkage rods 47 are pivotally connected, on the one hand, to the actuating carriage 42 and, on the other hand, to one of the grab buckets 34. The grab buckets 34 themselves are pivotally mounted on the lower end of the grab frame 32 via pivot bearings 35. By a relative displacement of the actuating carriage 42 with respect to the grab frame 32, the grab buckets 34 can be opened and closed. By a relative displacement of the actuating carriage 42 upwards, the linkage rods 47 are pulled upwards, whereby the grab bucket 34 is pivoted about its pivot axes 35 into its open position, which is clearly illustrated in Fig. 3. A pulley arrangement 50 for the actuating cable 44 is provided below the actuating carriage 42.The pulley assembly 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 possibly wrapped several times by the actuating cable 44 supplied from above, forming loops 56 or pulleys, with the lower end of the actuating cable 44 being fixedly connected to the gripper frame 32 or the actuating carriage 42. The actuating carriage 42 is thus adjustably connected or coupled to the gripper frame 32 via the actuating cable 44.

[0036] Starting from the opening position shown in Fig. 3, the actuating carriage 42 is pulled downward relative to the gripper frame 32 by the pulley assembly 50 by pulling the actuating cable 44 upwards through the second cable winch 22. The connecting rods 47 thereby press the gripper blades 34 downwards with an increased closing force, pivoting the gripper blades 34 about their pivot bearings 35 into the closed position shown in Fig. 2.

[0037] When used in a slot in the ground, soil material can be gripped and enclosed between the grab buckets 34 with a closing force that is higher than the tensile force on the actuating cable 44.

[0038] After the rope grab 30 is pulled out of a slot in the ground and moved to an emptying position, the tensile force on the actuating rope 44 can be reduced. In this way, the grab frame 32 moves downward relative to the actuating carriage 42 due to its weight, so that the grab blades 34 are pivoted back into their open position via the linkage rods 47, as shown in Fig. 3.

[0039] This described arrangement is only an example. In principle, other pulley arrangements with different rope linkages and a different linkage mechanism can be selected, enabling comparable grapple bucket operation.

[0040] When operating the rope grab 30, it is necessary to coordinate the forces and movements between the holding rope 24 and the actuating rope 44 in order to control the torques in the individual ropes and thus the torques of the attached rope grab 30 about its longitudinal axis, particularly due to a so-called lay direction in wound rotating ropes, so that a desired rotation of the rope grab 30 only occurs when this is necessary for the construction process.

[0041] According to the invention, forces in the holding 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 pulleys on the head 20 of the boom 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 a stabilization of the rotational position of the cable gripper 30 about its longitudinal axis or a targeted rotation desired by the machine operator is achieved. The machine operator only needs to make corresponding inputs regarding a possibly desired compensation mode for position stabilization or inputs regarding a desired rotational position of the steep gripper 30. Based on this, the control device can control the cable winches 21, 22 accordingly in order to bring about the desired rotational position of the cable gripper 30.This makes the control of a simply constructed rope gripper 30 considerably easier and simpler for a machine operator.

Claims

PATENT CLAIMS 1 gripper device with a carrier device (12) and a cable gripper (30) arranged thereon, which has a gripper frame (32) which is held on the carrier device (12) via a holding cable (24) and can be lowered and raised via the holding cable (24), at least two gripper blades (34) which are pivotally mounted at a lower end of the gripper frame (32) between a closed position and an open position, and an actuating device (40) with an actuating cable (44) for opening and closing the gripper blades (34), wherein the actuating cable (44) is guided from the carrier device (12) to the actuating device (40), the carrier device (12) has a driven first cable winch (21) for the holding cable (24) and a driven second cable winch (22) for the actuating cable (44), and a control device with an input unit is arranged, characterized in thatthat for filling the grab buckets, a cycle number for opening and closing the grab buckets (34) and / or for raising and lowering the rope grab (30) can be entered into the control device by the input unit, and that the control device is designed to automatically open and close the grab buckets (34) repeatedly or to raise and lower the rope grab (30) repeatedly in accordance with the entered cycle number.

2. Gripper device according to claim 1, characterized in that a first detection device is designed to detect a filling level of the gripper blades (34).

3. Gripper device according to claim 2, characterized in that the first detection device comprises at least one sensor for detecting a cable tensile force.

4. Gripper device according to one of claims 1 to 3, characterized in that at least one second detection device is designed to detect a vertical position of the rope gripper (30).

5. Gripper device according to one of claims 1 to 4, characterized in 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.

6. Gripper device according to one of claims 1 to 5, characterized in that at least one third detection device is designed to detect a rotational position of the rope gripper (30) and / or a change in the rotational position.

7. Gripper device according to one of claims 1 to 3, characterized in that the control device is designed to determine a specification for a number of cycles and / or a lowering height and / or to suggest it to an operator depending on detected values ​​of at least one of the detection devices, in particular depending on a detected fill level. Gripper device according to one of claims 1 to 7, characterized in that the actuating device has an actuating carriage (42) which is connected to the gripper blades (34) via a linkage mechanism (46), and in that the actuating carriage (42) is displaceable along the gripper frame (32) for pivoting the gripper blades (34). Gripper device according to claim 8, characterized in that a pulley arrangement (50) is provided on the actuating carriage (42), with which an increase in force for closing the gripper blades (34) can be generated. Gripper device according to one of claims 1 to 9, characterized in that the input unit has a control panel for an operator. Gripper device according to one of claims 1 to 10, characterized in that a display screen is provided for the control device.Method for operating a gripper device, in particular according to one of claims 1 to 11, with a cable gripper (30) which has a gripper frame (32) which is held on a carrier device (12) via a holding cable (24) and can be lowered and raised via the holding cable (24), at least two gripper blades (34) which are mounted at a lower end of the gripper frame (32) so as to be pivotable between a closed position and an open position, and an actuating device (40) with an actuating cable (44) for opening and closing the gripper blades (34). wherein the actuating cable (44) is guided from the carrier device (12) to the actuating device (40), the carrier device (12) has a driven first cable winch (21) for the holding cable (24) and a driven second cable winch (22) for the actuating cable (44), and a control device with an input unit is arranged, characterized in that for filling the grab buckets, a cycle number for opening and closing the grab buckets (34) and / or for raising and lowering the cable grab (30) is entered into the control device, and that the grab buckets (34) are repeatedly opened and closed or the cable grab (30) is repeatedly raised and lowered by the control device in accordance with the entered cycle number.

13. Method according to claim 12, characterized in that soil is removed by means of the rope gripper (30) and in particular a slot is created in the soil.

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