GRAB DEVICE AND METHOD FOR OPERATING GRAB DEVICE

Abstract

The present invention relates to a grab device comprising a transporter and a rope grab arranged on the transporter, the rope grab comprising a grab frame held on the transporter by a holding rope, at least two grab shovels pivotably supported at the lower end of the grab frame between a closed position and an open position, and an actuating means with an actuating rope for turning the grab shovel, the actuating rope being guided from the transporter to the actuating means, the transporter comprising a driven first rope winch for the holding rope and a driven second rope winch for the actuating rope. According to the invention, a first detection means for detecting a first rope force on the holding rope and a second detection means for detecting a second rope force on the actuating rope are provided, and a control means connected to the first detection means, the second detection means, the first rope winch and the second rope winch is provided, the control means being designed to actuate the first rope winch and / or the second rope winch according to a control program specification depending on the detected first rope force on the holding rope and the detected second rope force on the actuating rope.

Description

[Technical field]

[0001] The present invention relates to a grab device according to the preamble of claim 1, comprising a transport machine and a rope grab arranged on the transport machine, the rope grab having a grab frame held on the transport machine by a holding rope, at least two grab shovels pivotably supported at the lower end of the grab frame between a closed position and an open position, and an actuating means with an operating rope for pivoting the grab shovels, the operating rope being guided from the transport machine to the actuating means, the transport machine having a driven first rope winch for the holding ropes and a driven second rope winch for the operating ropes.

[0002] The invention further relates to a method for operating a grab device according to the preamble of claim 13. [Background technology]

[0003] In professional foundation engineering, grab equipment is used to create trenches in the earth, within which diaphragm walls can be created to maintain and / or seal the excavated pit.

[0004] The grab device mainly comprises a grab with several grab shovels, which are suspended by means of holding ropes on a transporter (usually a boom crane). The holding ropes can be used to lower the grab into the ground. By closing the grab shovels, the earth mass can be removed from the ground and received in the grab. The grab is then further pulled out of the ground via the holding ropes and swung together with the transporter to an emptying position, where the grab shovels are opened to dump the earth mass. The grab is then swung back to the working position and guided into the underground trench for a new grabbing process.

[0005] The grabs used in such grab devices are of two different types: hydraulic grabs and rope grabs. So-called hydraulic grabs are known, for example, from EP 3798367 A1. In hydraulic grabs, the opening and closing movement of the grab shovel is generated by a hydraulic cylinder arranged on the grab frame.

[0006] Such hydraulic grabs can be operated and controlled relatively simply by means of a hydraulic system. However, suitable hydraulic lines running parallel to the holding ropes are required for the supply and discharge of hydraulic fluid. The transport machine must be provided with a correspondingly designed hydraulic unit as well as corresponding line reels for the hydraulic lines with the respective winch drives. This makes the grab device correspondingly larger and more expensive. Furthermore, the hydraulic system requires additional maintenance.

[0007] In comparison, so-called rope grabs offer a rather simplified construction. Such a type of rope grab is known, for example, from GB 2126981A. In rope grabs, the opening and closing movement of the grab shovel is brought about by an actuating rope, which runs substantially parallel to the holding rope from the actuating means of the grab shovel to the transporter. Using a separate winch for the actuating rope, opening and closing of the grab shovel can be achieved by unwinding or winding the actuating rope from or onto the winch.

[0008] With rope grabs, the need for complex hydraulic line supply to the grab can be omitted. All that is required is an additional operating rope together with the corresponding winch. Such operating ropes also require significantly less maintenance compared to hydraulic lines with corresponding hydraulic systems.

[0009] However, the operation of rope grabs requires an experienced machine operator and is not as simple as that of hydraulic grabs. One of the reasons for this is mainly that the double rope arrangement, i.e. the holding rope and the working rope, generates torques in the various operating states, which cause the rope grab to rotate to a certain extent around its longitudinal axis. However, when returning the rope grab from the emptying position, a correct rotational position of the rope grab is essential in order to be able to guide it again into the trench already made in the ground.

[0010] The rotational position of the rope grab around its longitudinal axis can be brought about by the machine operator applying a certain tension to the holding rope and the working rope. This requires a relatively delicate operation of the respective rope winch. On the part of the machine operator, high concentration is also required when carrying out this method, along with a certain experience. Moreover, since the rope winch is often operated by a foot pedal, the delicate operation of the rope winch for several hours is also very tiring for the machine operator. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] European Patent Application Publication No. 3798367 [Patent Document 2] UK Patent Application Publication No. 2126981 Summary of the Invention [Means for solving the problem]

[0012] The invention is based on the object of providing a grab device and a method for operating the grab device, which at the same time allows easy operation while still providing a simple structure of the grab device.

[0013] This object is achieved on the one hand by a grab device having the features of claim 1 and on the other hand by a method having the features of claim 13. Particular embodiments of the invention are set out in the respective dependent claims.

[0014] The grab device according to the present invention is characterised in that it is provided with a first detection means for detecting a first rope force on the holding rope and a second detection means for detecting a second rope force on the working rope, and it is provided with a control means connected to the first detection means, the second detection means, the first rope winch and the second rope winch, the control means being designed to operate the first rope winch and / or the second rope winch according to control program specifications depending on the detected first rope force on the holding rope and the detected second rope force on the working rope.

[0015] The invention is based on the finding that the torque on the rope grab around its longitudinal axis depends on the rope forces on the holding and working ropes. Thus, according to one aspect of the invention, detection means are provided, with which the rope forces on the holding and working ropes are detected. The force values ​​detected in each situation can be transferred to a control means which controls a first rope winch for the holding rope and a second rope winch for the working rope according to the input and specifications by the machine operator. Thus, the control means allows the forces on the holding and working ropes to be matched to each other through the corresponding actuation (winding / unwinding of the rope) of the respective rope winches, so that no torque is generated around the longitudinal axis on said rope grab by the holding and working ropes, especially when the rope grab is in a given or desired rotational position. Basically, the control means can also be used to generate a defined (variable) torque for a desired turn, by influencing the respective rope forces accordingly.

[0016] Furthermore, the invention is based on the finding that in the normal use of steel ropes, in particular made from a number of spiral steel wires or strands, a so-called rope twist is present, which in the case of steel ropes that are not slow-twisting or rotation-resistant leads to a torque around the longitudinal axis of the rope when a corresponding tensile force is applied to the steel rope. If the holding rope and the working rope show opposite twist directions, these torques generated by the ropes can be compensated by matching the tensile forces in the holding rope with the tensile forces in the working rope. This can be achieved particularly simply when ropes of the same or similar construction but with opposite twist directions are used. When using two ropes with opposite rope twist attached to one body, a torque balance, a left-handed torque or a right-handed torque can be generated in the body if there is a corresponding tensile force distribution. The holding ropes can preferably be fixed to the upper or lower area of ​​the grab frame or the actuation means.

[0017] In a preferred embodiment of the invention, a defined ratio between the first rope force on the holding rope and the second rope force on the working rope can be specified and set by the control program specification of the control means. The control program specification can take into account allowances for identical or different designs of the holding rope and the working rope accordingly. Torque compensation can be achieved by setting substantially equal tensions for the holding rope and the working rope, which are preferably identical in design, but have opposite rope twist. Allowances for different rope designs for different rope configurations can be made and preset accordingly in the control program specification. Additional geometric conditions of the rope grab, for example conditions related to the various attachment points of the ropes on the grab frame, can also be preset and taken into account in the control program specification.

[0018] In another preferred embodiment of the invention, the control means is designed with a compensation mode, in which the rope winches are operated such that the first rope force on the holding rope and the second rope force on the working rope match each other. In particular, the rope winches can be operated such that the torques on the working rope and the torques on the holding rope compensate each other and cancel each other out. In this way, the rotational position of the rope grab around its longitudinal axis can be stabilized. Undesired rotations of the rope grab around its longitudinal axis during operation can thus be largely avoided.

[0019] In particular, according to a further development of the invention, the control means is advantageously designed with a turning mode, in which the rope winch is operated so as to be able to generate a target turning of the rope grab around the vertical longitudinal axis. Starting from a stable turning position, the machine operator can bring about a desired change in the turning position by appropriately operating the rope winch, preferably via an input device, such as for example a thumb wheel of a joystick. The control means can also be designed in such a way that the machine operator specifies the value or degree of the desired turning by means of the input means, and according to the program logic, the winch is operated by the control means in such a way that the desired changed turning position is reached.

[0020] According to a further development of the invention, at least a third detection means is preferably provided for detecting the rotational position and / or the change in the rotational position of the rope grab. This can be done by optical detection means, a rotation transducer, a gyroscope on the rope grab or any other suitable means. Thus, when actuated by the control means, a feedback can be given to the rotational position or turn of the grab so that an adjustment of the rotational position or an adjustment of the turn can be carried out. This allows a particularly accurate setting of the rotational position of the rope grab.

[0021] According to another embodiment of the invention, a further improvement in the operability is provided by providing at least one further detection means, in particular for detecting the vertical position of the rope grab, the distance and / or the angular position of the rope grab relative to the transport machine. The additional parameters thus detected can be displayed directly to the machine operator and / or processed by the control means for controlling the grab.

[0022] In another advantageous embodiment of the invention, an operating panel for manual control for actuating the rope grab and / or the rope winch is provided. The operating panel as input means is preferably designed in such a way that the desired turning or movement, in particular of the rope grab, is input by the machine operator, for example as a numerical value or an angular measurement, via suitable operating elements, in particular combined with a display, such as a cursor, a rotary wheel, a switch or a key. Thus, direct input of the winch and of the winch rotation by the machine operator is not required. In practice, according to said operating input regarding the position of the grab, the machine with the respective motor and the positioning member is operated via a control means with a program logic in such a way that the desired position is approximately reached without undesired turning movements.

[0023] According to a variant embodiment of the invention, it is particularly preferred that the control means is designed with an automatic program by means of which the rope grab can be moved automatically to the emptying position and / or to the removal position. The automatic program can be permanently stored or, in the case of repetitive processes, can be defined and saved individually by the machine operator. In this way, larger movement sequences of the grab can be performed automatically, in particular the movement to the emptying position and / or back to the removal position. Such movement distances of the rope grab occur with a high repetition frequency, in particular when making deep trenches in the ground.

[0024] Basically, the individual ropes may be of the same or different design. According to an embodiment of the present invention, it is particularly advantageous if the holding rope on the first rope winch has a first turn, which turns opposite to the second turn of the working rope on the second rope winch. In particular, the holding rope and the working rope have opposite twisting directions, the so-called rope twist. When tension is applied, the ropes generate opposite torques. This facilitates torque compensation for stabilizing the position of the rope grab during operation.

[0025] Basically, the actuating rope can be directly connected to the grab shovel. In order to achieve the maximum possible closing force, according to a further development of the invention, it is advantageous for the actuating means to have an actuating carriage connected to the grab shovel by a linkage mechanism, and for the actuating carriage to be displaceable along the grab frame in order to pivot the grab shovel. Preferably, the actuating carriage is supported on the grab frame so as to be displaceable in the longitudinal or vertical direction. The linkage mechanism may comprise a joint, a linking rod or a linking rope. In particular, the actuating carriage allows the realization of an opening and closing movement of the grab shovel that is as uniform as possible, which is advantageous for stabilizing the position of the rope grab.

[0026] Optionally, a pulley block device is provided adjacent to the working carriage, with which an increase in force for closing and / or opening the grab shovel can be generated, so that a particularly high closing force can be achieved. By means of the pulley block device, a doubling of the force on the working rope for opening and closing the grab shovel can be achieved depending on the number of pulls. The pulley block device is specifically arranged between the working carriage and the lower end of the grab frame. The pulley of the pulley block device is supported on the one hand on the working carriage and on the other hand on the grab frame, around which the working rope can be wound, the lower end of which is fixed to the grab frame. As a result, the distance covered by the rope is correspondingly extended, so that the working carriage can be operated with the desired increase in force.

[0027] According to a further embodiment of the invention, it is particularly advantageous if a display screen for the control means is provided for operation. The display screen can in particular be designed as a touch screen, on which at least some of the operating elements for the machine operator are implemented. Furthermore, the position of the rope grab can be displayed in various representations on the display screen, which makes the operation even easier for the machine operator.

[0028] The present invention further comprises a method for operating a grab apparatus, in which the above-mentioned grab apparatus according to the present invention is used, a first rope force on the holding rope is detected by a first detection means and a second rope force on the working rope is detected by a second detection means, the first detection means, the second detection means, the first rope winch and the second rope winch are connected to a control means, and in response to the detected first rope force on the holding rope and the detected second rope force on the working rope, the control means operates the first rope winch and / or the second rope winch according to specifications of a control program.

[0029] Through this method, the aforementioned advantages can be achieved in conjunction with the grab device according to the invention.

[0030] The grab device can be used in particular for various tasks. In a preferred method variant, the soil is removed by means of a rope grab, in particular for creating trenches in the ground. The rope grab can be designed in particular as a so-called diaphragm wall grab, with which trenches can be created for underground cut-off walls and / or retaining walls, for example for excavation pit enclosures.

[0031] The invention is further explained below by way of preferred embodiments which are illustrated diagrammatically in the drawings. [Brief description of the drawings]

[0032] [Figure 1] 1 is a perspective view of a grab device according to the present invention; [Diagram 2] FIG. 2 is a front view of the rope grab of the grab device of FIG. 1 with the grab shovel closed. [Diagram 3] FIG. 3 is a front view of the rope grab according to FIG. 2 with an open grab shovel. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] The grab device 10 according to the invention according to Fig. 1 has a mobile transporter 12 with a caterpillar track as a lower carriage 14. On the lower carriage 14 an upper carriage 16 with an operator's cab 17 is supported rotatably about a vertical axis of rotation. Inside the operator's cab 17 control means are arranged, including input means for the machine operator.

[0034] On the upper carriage 16, a boom arm 18 is connected so as to be rotatable about a horizontal axis. A head 20 of the boom arm 18 with a deflection pulley guides a holding rope 24, at the end of which a rope grab 30 with a grab frame 32 and a number of lower grab shovels 34 is suspended. Via a first rope winch 21 of the transporter 12, the holding rope 24 can be actuated to raise and lower the rope grab 30. In addition, a second rope winch 22 is arranged on the transporter 12 for actuating a rope 44, which is also guided through the head 20 to the rope grab 30 and actuates the grab shovels 34 at the lower end of the grab frame 32.

[0035] The function of the grab device 10 according to the invention will be explained in more detail below in conjunction with FIGS.

[0036] In the central region of the grab frame 32, an operating carriage 42 of an operating means 40 is supported so as to be displaceable in the vertical longitudinal direction in order to operate the grab shovel 34. Since an end of the holding rope 24 is fixed to the upper end of the operating carriage 42, the rope grab 30 is held via the operating carriage 42.

[0037] At the lower end of the working carriage 42, a coupling mechanism 46 with a coupling rod 47 is arranged. The coupling rod 47 is rotatably coupled to the working carriage 42 on the one hand and to one of the grab shovels 34 on the other hand. The grab shovel 34 itself is rotatably supported by a pivot support 35 at the lower end of the grab frame 32. The grab shovel 34 can be opened or closed by the relative displacement of the working carriage 42 with respect to the grab frame 32. The upward relative displacement of the working carriage 42 pulls the coupling rod 47 upwards, which causes the grab shovel 34 to rotate about the pivot axis 35 until it is in the open position shown in FIG. 3.

[0038] Below the working carriage 42, a pulley block device 50 for the working rope 44 is provided. The pulley block device 50 has an upper pulley 52 rotatably supported on the working carriage 42 and a lower pulley 54 rotatably supported in the lower region of the grab frame 32. Around the pulleys 52, 54, the working rope 44 fed from above is wound several times by forming a number of loops 56 or tightenings, while the lower end of the working rope 44 is firmly connected to the grab frame 32. Thus, via the working rope 44, the working carriage 42 is adjustably connected or coupled to the grab frame 32.

[0039] Starting from the open position according to Fig. 3, the second rope winch 22 pulls the operating rope 44 upward, so that the operating carriage 42 is pulled downward relative to the grab frame 32 by the pulley block device 50. At that time, the connecting rod 47 pushes the grab shovel 34 downward with an increased closing force, so that the grab shovel 34 is rotated around the pivot support 35 to the closed position according to Fig. 2.

[0040] When used in underground trenches, an increased closing force in relation to the tension on the operating ropes 44 can be used to grab and trap earth masses between the grab shovels 34 .

[0041] After the rope grab 30 is pulled out of the underground trench and moved to the emptying position, the tension on the working rope 44 can be reduced. As a result, the grab frame 32 is displaced downwards relative to the working carriage 42 by its own weight, so that the grab shovel 34 is rotated back to the open position by the connecting rod 47, as shown in FIG. 3.

[0042] The described configuration is merely exemplary: in principle, other types of pulley block arrangements with different rope connections and other connection mechanisms can be selected, which allow the operation of a comparable grab shovel.

[0043] In order for the torque of the individual ropes, and therefore the torque of the suspended rope grab 30 about its longitudinal axis, to be controlled so that the desired rotation of the rope grab 30 occurs only when required for the construction to proceed, it is necessary to match the forces and movements between the holding ropes 24 and the actuating ropes 44 when operating the rope grab 30, especially since in the case of twisted ropes there is a so-called twist direction.

[0044] According to the invention, the forces on the holding rope 24 and the actuating rope 44 are detected via corresponding detection means, which can be arranged, for example, on the rope winches 21, 22 or on the deflection pulleys on the head 20 of the boom arm 18. Via control means, preferably arranged in the cab 17 of the transport machine 12, the winches 21, 22 can be activated depending on the detected rope forces, so that either a stabilization of the rotational position of the rope grab 30 about its longitudinal axis or a target turn desired by the machine operator is achieved. All that is required on the part of the machine operator is a corresponding input related to the desired compensation mode that can be assumed for the position stabilization or an input related to the desired rotational position of the rope grab 30. On this basis, the control means can activate the rope winches 21, 22 accordingly in order to bring about the desired rotational position of the rope grab 30. As a result, the control of the rope grab 30 of simple construction is simplified and facilitated to a great extent for the machine operator.

Claims

1. A grab device comprising a transport machine and a rope grab disposed on the transport machine, The rope grab is A grab frame suspended and supported on the transport machine by a support rope; At least two grab shovels rotatably supported on a lower end of the grab frame between a closed position and an open position; and an operating means having an operating rope extending parallel to the holding rope for rotating the grab shovel, The actuation rope is guided from the transport machine to the actuation means, the transport machine having a driven first rope winch for the holding rope and a driven second rope winch for the working rope; a first detection means for detecting a first rope force on the holding rope and a second detection means for detecting a second rope force on the actuation rope; a control means is provided connected to the first detection means, the second detection means, the first rope winch and the second rope winch, the control means being designed to operate the first rope winch and / or the second rope winch according to control program specifications in response to the detected first rope force on the holding rope and the detected second rope force on the actuation rope; the control means is designed to have a compensation mode, in which the control means actuates the first and second rope winches to match the first and second rope forces with each other and to compensate for torque about the longitudinal axis of the rope due to twist in the rope caused by the first and second rope forces. Grab device.

2. A grab device comprising a transport machine and a rope grab disposed on the transport machine, The rope grab is A grab frame suspended and supported on the transport machine by a support rope; At least two grab shovels rotatably supported on a lower end of the grab frame between a closed position and an open position; and an operating means having an operating rope extending parallel to the holding rope for rotating the grab shovel, The actuation rope is guided from the transport machine to the actuation means, the transport machine having a driven first rope winch for the holding rope and a driven second rope winch for the working rope; a first detection means for detecting a first rope force on the holding rope and a second detection means for detecting a second rope force on the actuation rope; a control means is provided connected to the first detection means, the second detection means, the first rope winch and the second rope winch, the control means being designed to operate the first rope winch and / or the second rope winch according to control program specifications in response to the detected first rope force on the holding rope and the detected second rope force on the actuation rope; the control means is designed to have a turning mode, in which the control means actuates the first and second rope winches to control the torque about the longitudinal axis of the rope due to the twist of the rope caused by the first and second rope forces to generate a target turning of the rope grab about a vertical longitudinal axis. Grab device.

3. 3. The grab apparatus according to claim 2, wherein the control program specification of the control means allows a prescribed ratio to be specified and set between the first rope force on the holding rope and the second rope force on the actuation rope.

4. A grab device as described in claim 1 or 2, wherein at least a third detection means is provided for detecting the rotational position of the rope grab around the vertical longitudinal axis and / or a change in the rotational position.

5. 3. The grab device according to claim 1 or 2, wherein at least one further detection means is provided for detecting the vertical position of the rope grab, the distance and / or the angular position of the rope grab relative to the transport machine.

6. 3. The grab apparatus according to claim 1 or 2, wherein the retaining rope on the first rope winch is twisted in a first twist direction, the first twist direction being opposite to a second twist direction of the actuation rope on the second rope winch.

7. The actuating means has an actuating carriage connected to the grab shovel by a coupling mechanism, The grab device according to claim 1 or 2, wherein the actuating carriage is displaceable along the grab frame to rotate the grab shovel.

8. The grab device according to claim 7, further comprising a pulley block device provided adjacent to the working carriage, the pulley block device being capable of generating an increase in force for closing and / or opening the grab shovel.

9. 3. The grab apparatus according to claim 1 or 2, further comprising an operating panel for manual control to operate the rope grab and / or the first and second rope winches.

10. 3. The grab device according to claim 1 or 2, wherein a display screen for the control means is provided for operation.

11. 1. A method for operating a grab device, comprising: The grab device according to claim 1 is used, The first rope force applied to the holding rope is detected by the first detection means, the second rope force on the actuation rope is detected by the second detection means; the first detection means, the second detection means, the first rope winch, and the second rope winch are connected to a control means; said first rope winch and / or said second rope winch are operated by said control means in response to the detected first rope force on said holding rope and the detected second rope force on said working rope according to a control program specification; In the compensation mode, the control means operates the first and second rope winches to match the first and second rope forces to each other and to compensate for torque about the longitudinal axis of the rope due to twist in the rope caused by the first and second rope forces. method.

12. 1. A method for operating a grab device, comprising: The grab device according to claim 2 is used, The first rope force applied to the holding rope is detected by the first detection means, the second rope force on the actuation rope is detected by the second detection means; the first detection means, the second detection means, the first rope winch, and the second rope winch are connected to a control means; said first rope winch and / or said second rope winch are operated by said control means in response to the detected first rope force on said holding rope and the detected second rope force on said working rope according to a control program specification; In the turning mode, the control means actuates the first and second rope winches to control torque about the longitudinal axis of the rope due to twist in the rope caused by the first and second rope forces to generate a target turning of the rope grab about a vertical longitudinal axis. method.

13. 13. The method according to claim 11 or 12, wherein the rope grab is used to remove soil, in particular to create a trench in the ground.

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