EP4134489A1 - Gripper device and method for operating a gripper device - Google Patents

Abstract

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 retaining cable, at least two gripper shovels which are pivotably mounted at a lower end of the gripper frame between a closed position and an open position, and an actuating device with an actuating cable for pivoting the grab scoops, an actuating cable being guided from the carrier device to the actuating device, and the carrier device having a driven first cable winch for the retaining cable and a driven second cable winch for the actuating cable. According to the invention, it is provided that a first detection device is provided for detecting a first cable force on the retaining cable and a second detection device is provided for detection of a second cable force on the actuating cable and that a control device is provided which is connected to the first detection device, the second detection device, the first cable winch and the second cable winch is connected and is designed to control the first cable winch and/or the second cable winch according to a control program specification depending on the detected first cable force on the tether and the detected second cable force on the actuating cable.

Description

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 retaining cable, at least two gripper shovels which are pivotably mounted at a lower end of the gripper frame between a closed position and an open position, and has an actuating device with an actuating cable for pivoting the grab buckets, the actuating cable being guided from the carrier device to the actuating device, and the carrier device having a driven first cable winch for the retaining cable and a driven second cable winch for the actuating cable, according to the preamble of claim 1.

The invention also relates to a method for operating a gripper device according to the preamble of claim 13.

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

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

There are two different types of grabs used on such grab devices, namely hydraulic grabs and cable grabs. A so-called hydraulic gripper is, for example, from the EP 3 798 367 A1 known. In the case of a hydraulic grab, the movement for opening and closing the grab buckets is generated by a hydraulic cylinder which is arranged on the grab frame.

Such hydraulic grippers can be operated and controlled relatively easily by the hydraulic system. However, appropriate hydraulic lines are required for supplying and removing hydraulic fluid, which run parallel to the tether. Appropriate cable drums for the hydraulic lines with appropriate winch drives and an appropriately designed hydraulic system are to be provided on the carrier device. As a result, the gripper device is correspondingly enlarged and also more expensive. The hydraulic system also requires additional maintenance.

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

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

However, operating a rope grab is not as easy as operating a hydraulic grab and requires an experienced machine operator. One reason for this is that due to the double arrangement of a cable, namely the holding cable and the actuating cable, torques are generated in different operating states, which cause a certain twisting of the cable gripper about its longitudinal axis. However, an exact rotational position of the cable gripper is essential in order to be able to insert the cable gripper back into a slot that has already been created in the ground when it is returned from the emptying position.

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

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

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 13 . Particular embodiments of the invention are specified in the respective dependent claims.

The gripper device according to the invention is characterized in that a first detection device is provided for detecting a first cable force on the retaining cable and a second detection device is provided for detecting a second cable force on the actuating cable and that a control device is provided which is connected to the first detection device, the second detection device, the first cable winch and the second cable winch is connected and is designed depending on the detected first cable force on the tether and the detected second cable force to control the first cable winch and/or the second cable winch on the actuating cable in accordance with a control program specification.

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

The invention is also based on the finding that, particularly with the usual use of steel cables made of coiled steel wires or strands, there is a so-called cable lay, which in the case of non-rotational or rotation-free steel cables leads to a torque about the longitudinal axis of the cable when corresponding tensile forces are applied to the steel cable. Provided that the tether and the actuating cable have an opposite direction of lay, these torques generated by the cables can be compensated for by matching the tensile forces in the tether and the actuating cable. Preferably, this can be achieved in a particularly simple manner if identically or similarly constructed ropes are used, which, however, have an opposite direction of lay. When using two ropes with an opposite rope lay, which are attached to a body, a torque balance, a left-hand rotation or a right-hand rotation torque can be generated on the body with a corresponding tensile force distribution. The tether can preferably at one attached to the top or bottom of the gripper frame or actuator.

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

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

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

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

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

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

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

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

In principle, the actuating cable can be articulated directly on the grab shovels. In order to achieve the highest possible closing forces, it is advantageous according to a development of the invention that the actuating device has an actuating carriage which is connected to the gripper scoops via a linkage mechanism, and that the actuating carriage can be displaced along the gripper frame to pivot the gripper scoops. The actuating carriage is preferably mounted on the gripper frame such that it can be displaced in a longitudinal direction or in a vertical direction. The articulation mechanism can include joints, articulation rods or articulation cables. In particular, an opening and closing movement of the grab scoops that is as uniform as possible can be effected by an actuating carriage. This is advantageous for stabilizing the position of the cable gripper.

Particularly high closing forces can preferably be achieved in that a pulley arrangement is provided on the actuating carriage, with which an increase in force for closing and/or opening the grab shovels can be generated. By means of a block and tackle arrangement, the force on the actuating cable for opening and closing the grab scoops can be multiplied, depending on the number of trains. In particular, the pulley arrangement is positioned between the actuating carriage and the lower end of the gripper frame. The rollers of the block and tackle arrangement, which are mounted on the one hand on the actuating carriage and on the other hand on the gripper frame, can be looped around by the actuating cable, the lower end of which is attached to the gripper frame. This results in a corresponding lengthening of the path of the cable for actuating the actuating carriage with the desired increase in force.

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

The invention further includes a method for operating a gripper device, wherein the gripper device according to the invention described above is used, wherein a first cable force on the retaining cable is detected by a first detection device and a second cable force on the actuating cable is detected by a second detection device, and that the first detection device , the second detection device, the first cable winch and the second cable winch are connected to a control device, through which, depending on the detected first cable force on the retaining cable and the detected second cable force on the actuating cable, the first cable winch and/or the second cable winch according to a control program specification be controlled.

With the method, the advantages described above can be achieved with the gripper device according to the invention.

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

Fig. 1

eine perspektivische Ansicht einer erfindungsgemäßen Greifervorrichtung;

Fig. 2

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

Fig.3

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

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

1

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

2

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

Fig.3

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

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

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

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

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

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

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

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

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

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

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

When the cable gripper 30 is actuated, the forces and movements between the retaining cable 24 and the actuating cable 44 must be coordinated in order to reduce the torques in the individual cables and thus the torques of the attached cable gripper 30 about its longitudinal axis so to control that only a desired rotation of the cable gripper 30 occurs when this is required for the construction process.

According to the invention, forces in the retaining cable 24 and the actuating cable 44 are detected via corresponding detection devices, which can be arranged, for example, on the cable winches 21, 22 or on the deflection rollers at the head 20 of the cantilever arm 18. Via a control device, which is preferably arranged in the operator's cabin 17 on the carrier device 12, the winches 21, 22 can be controlled depending on the detected cable forces in such a way that either the rotational position of the cable gripper 30 is stabilized about its longitudinal axis or a specific position desired by the machine operator twist is achieved. On the part of the machine operator, all that is necessary are corresponding inputs for a possibly desired compensation mode for position stabilization or inputs for 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 simplifies and facilitates the control of a simply constructed cable gripper 30 to a considerable extent for a machine operator.

Claims (14)

Gripper device with a carrier device (12) and a cable gripper (30) arranged thereon, which - a gripper frame (32) which is held on the carrier device (12) via a retaining cable (24), - at least two grab scoops (34) which are pivotally mounted at a lower end of the grab frame (32) between a closed position and an open position, and - has an actuating device (40) with an actuating cable (44) for pivoting the grab shovels (34), - wherein an actuating cable (44) is guided from the carrier device (12) to the actuating device (40) and - the carrier device (12) has a driven first cable winch (21) for the retaining cable (24) and a driven second cable winch (22) for the actuating cable (44),
characterized, - that a first detection device for detecting a first cable force on the retaining cable (24) and a second detection device for detecting a second cable force on the actuating cable (44) are provided and - that a control device is provided, which is connected to the first detection device, the second detection device, the first cable winch (21) and the second cable winch (22) and is designed depending on the detected first cable force on the retaining cable (24) and the detected second cable force on the actuating cable (44) to control the first cable winch (21) and/or the second cable winch (22) according to a control program specification. Gripper device according to claim 1,
characterized,
that a defined ratio between the first cable force in the retaining cable (24) and the second cable force in the actuating cable (44) can be specified and adjusted by the control program specification of the control device. Gripper device according to claim 1 or 2,
characterized,
that the control device is designed with a compensation mode in which the cable winches (21, 22) are controlled in such a way that the first cable force on the retaining cable (24) and the second cable force on the actuating cable (44) are matched to one another. Gripper device according to one of claims 1 to 3,
characterized,
that the control device is designed with a twisting mode in which the cable winches (21, 22) are controlled in such a way that a targeted twisting of the cable gripper (30) about a vertical longitudinal axis can be generated. Gripper device according to one of claims 1 to 4,
characterized,
that at least one third detection device is provided for detecting a rotational position of the cable gripper (30) and/or a change in the rotational position. Gripper device according to one of claims 1 to 5,
characterized,
that at least one further detection device is provided, in particular for detecting a vertical position of the cable gripper (30), a distance and/or an angular position of the cable gripper (30) from the carrier device (12). Gripper device according to one of claims 1 to 6,
characterized,
that the control device is designed with an automatic program, by means of which the cable gripper (30) can be automatically moved to an emptying position and/or to a removal point. Gripper device according to one of claims 1 to 7,
characterized,
that the tether (24) on the first winch (21) has a first winding which is opposite to a second winding of the actuating cable (44) on the second winch (22). Gripper device according to one of claims 1 to 8,
characterized, that the actuating device has an actuating carriage (42) which is connected to the gripper shovels (34) via a linkage mechanism (46), and that the actuating slide (42) can be displaced along the gripper frame (32) in order to pivot the gripper shovels (34). Gripper device according to claim 9,
characterized,
that a pulley arrangement (50) is provided on the actuating carriage (42), with which an increase in force for closing and/or opening the gripper scoops (34) can be generated. Gripper device according to one of claims 1 to 10,
characterized,
that a control panel for a manual control for actuating the cable gripper (30) and/or the cable winches (21, 22) is provided. Gripper device according to one of claims 1 to 11,
characterized,
that a display screen for the control device is provided for operation. Method for operating a gripper device,
characterized, that a gripper device (10) according to one of Claims 1 to 12 is used, a first cable force on the retaining cable (24) being detected by a first detection device and a second cable force on the actuating cable (44) being detected by a second detection device, and that the first detection device, the second detection device, the first cable winch (21) and the second cable winch (22) are connected to a control device which, depending on the detected first cable force on the retaining cable (24) and the detected second cable force on the Actuating cable (44) the first cable winch (21) and / or the second cable winch (22) are controlled according to a control program specification. Method according to claim 12,
characterized,
that the ground is removed by means of the cable gripper (30) and in particular a slot is created in the ground.

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