GRAB DEVICE AND METHOD FOR OPERATING A GRAB DEVICE

Abstract

The invention relates to a grab device with a carrier implement and a rope grab arranged thereon which has a grab frame which is held on the carrier implement via a holding rope, at least two grab shovels which are pivotably supported on a lower end of the grab frame between a closed position and an open position, and an actuating means with an actuating rope for pivoting the grab shovels, wherein an actuating rope is guided from the carrier implement to the actuating means and the carrier implement has a driven first rope winch for the holding rope and a driven second rope winch for the actuating rope. In accordance with the invention provision is made in that 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 in that a control means is provided which is connected to the first detection means, the second detection means, the first rope winch and the second rope winch and which, depending on the detected first rope force on the holding rope and the detected second rope force on the actuating rope, is designed to activate the first rope winch and/or the second rope winch according to a control program specification.

Claims

1. A grab device with a carrier implement and a rope grab arranged thereon which has a grab frame which is held on the carrier implement via a holding rope, at least two grab shovels which are pivotably supported on a lower end of the grab frame between a closed position and an open position, and an actuating means with an actuating rope for pivoting the grab shovels, wherein an actuating rope is guided from the carrier implement to the actuating means and the carrier implement has a driven first rope winch for the holding rope and a driven second rope winch for the actuating rope, wherein 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 is provided which is connected to the first detection means, the second detection means, the first rope winch and the second rope winch and which, depending on the detected first rope force on the holding rope and the detected second rope force on the actuating rope, is designed to activate the first rope winch and/or the second rope winch according to a control program specification.

2. The grab device according to claim 1, wherein by the control program specification of the control means a defined ratio between the first rope force in the holding rope and the second rope force in the actuating rope is specified and can be set.

3. The grab device according to claim 1, wherein the control means is designed with a compensation mode, in which the rope winches are activated such that the first rope force on the holding rope and the second rope force on the actuating rope are matched to each other.

4. The grab device according to claim 1, wherein the control means is designed with a turning mode, in which the rope winches are activated such that a targeted turning of the rope grab about a vertical longitudinal axis can be generated.

5. The grab device according to claim 1, wherein at least a third detection means for detecting a rotational position of the rope grab and/or a change of the rotational position is provided.

6. The grab device according to claim 1, wherein at least one further detection means is provided, in particular for detecting a vertical position of the rope grab, a distance and/or an angular position of the rope grab with respect to the carrier implement.

7. The grab device according to claim 1, wherein the control means is designed with an automatic program, through which the rope grab can be moved automatically to an emptying position and/or to a removal location.

8. The grab device according to claim 1, wherein the holding rope on the first rope winch has a first winding which is opposed to a second winding of the actuating rope on the second rope winch.

9. The grab device according to claim 1, wherein the actuating means has an actuating carriage which is connected to the grab shovels via a linkage mechanism and the actuating carriage is displaceable along the grab frame for pivoting the grab shovels.

10. The grab device according to claim 9, wherein on the actuating carriage a pulley block arrangement is provided, with which a force increase for closing and/or opening the grab shovels can be generated.

11. The grab device according to claim 1, characterized in that an operating panel for manual control to actuate the rope grab and/or the rope winches is provided.

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

13. A method for operating a grab device, wherein a grab device according to claim 1 is employed, wherein a first rope force on the holding rope is detected by means of a first detection means and a second rope force on the actuating rope is detected by means of a second detection means, and the first detection means, the second detection means, the first rope winch and the second rope winch are connected to a control means, by which, depending on the detected first rope force on the holding rope and the detected second rope force on the actuating rope, the first rope winch and/or the second rope winch are activated according to a control program specification.

14. The method according to claim 12, wherein by means of the rope grab ground is removed and, in particular, a trench is produced in the ground.

Description

[0030] The invention is described further hereinafter by way of a preferred embodiment illustrated schematically in the drawings, wherein show

[0031] FIG. 1 a perspective view of a grab device according to the invention;

[0032] FIG. 2 a front view of the rope grab of the grab device of FIG. 1 with closed grab shovels; and

[0033] FIG. 3 a front view of the rope grab according to FIG. 2 with open grab shovels.

[0034] A grab device 10 pursuant to the invention and according to FIG. 1 has a mobile carrier implement 12 with a crawler-track running gear as undercarriage 14. On the undercarriage 14 an upper carriage 16 with an operator's cabin 17 is rotatably supported about a vertical axis of rotation. Inside the operator's cabin 17 a control means including an input means for a machine operator is located.

[0035] On the upper carriage 16 a boom arm 18 is pivotably linked about a horizontal axis. On a head 20 of the boom arm 18 with deflection pulleys a holding rope 24 is guided, on the end of which a rope grab 30 with a grab frame 32 and lower grab shovels 34 is suspended. By way of a first rope winch 21 on the carrier implement 12 the holding rope 24 can be actuated to lift and lower the rope grab 30. In addition, on the carrier implement 12 a second rope winch 22 for an actuating rope 44 is located which is also guided via the head 20 to the rope grab 30 to actuate the grab shovels 34 at the lower end of the grab frame 32.

[0036] The functioning of the grab device 10 according to the invention is explained in greater detail in the following in conjunction with FIGS. 2 and 3.

[0037] In a center region of the grab frame 32 an actuating carriage 42 of an actuating means 40 is displaceably supported in a vertical longitudinal direction in order to actuate the grab shovels 34. At the upper end of the actuating carriage 42 the end of the holding rope 24 is fixed so that the rope grab 30 is held via the actuating carriage 42.

[0038] At a lower end of the actuating carriage 42 a linkage mechanism 46 with linkage rods 47 is arranged. The linkage rods 47 are hinged on the one hand to the actuating carriage 42 and on the other hand to one of the grab shovels 34. The grab shovels 34 themselves are pivotably supported via pivot bearings 35 at the lower end of the grab frame 32. Through relative displacement of the actuating carriage 42 with respect to the grab frame 32 the grab shovels 34 can be opened and closed. Through relative displacement of the actuating carriage 42 in the upward direction the linkage rods 47 are pulled upwards, whereby the grab shovels 34 are pivoted about their pivot axes 35 into their open position which is illustrated graphically in FIG. 3.

[0039] Below the actuating carriage 42 a pulley block arrangement 50 for the actuating rope 44 is provided. The pulley block arrangement 50 has an upper pulley 52, which is rotatably supported on the actuating carriage 42, and a lower pulley 54, which is rotatably supported on a lower region of the grab frame 32. By forming loops 56 or pulls the pulleys 52, 54 are looped around several times by the actuating rope 44 supplied from above, while the lower end of the actuating rope 44 is firmly connected to the grab frame 32. By way of the actuating rope 44 the actuating carriage 42 is thus adjustably connected or coupled to the grab frame 32.

[0040] Starting from the open position according to FIG. 3, through upward-pulling of the actuating rope 44 by the second rope winch 22 the actuating carriage 42 is pulled by the pulley block arrangement 50 in the downward direction relative to the grab frame 32. In doing so, the linkage rods 47 press the grab shovels 34 with an increased closing force in the downward direction, whereby the grab shovels 34 are pivoted about their pivot bearings 35 into the closed position according to FIG. 2.

[0041] When used in a trench in the ground, ground material can in this way be grabbed and enclosed in-between the grab shovels 34 with a closing force that is increased with respect to the pull force on the actuating rope 44.

[0042] After withdrawing the rope grab 30 from a trench in the ground and after moving it to an emptying position the pull force on the actuating rope 44 can be reduced. As a result, the grab frame 32 is displaced due its weight force in the downward direction relative to the actuating carriage 42 so that the grab shovels 34 are pivoted via the linkage rods 47 back into their open position, as shown in FIG. 3.

[0043] This arrangement described is merely of exemplary nature. In principle, other types of pulley block arrangements with different rope linkages and a different linkage mechanism can also be chosen that enable a comparable grab shovel actuation.

[0044] When actuating the rope grab 30 a matching of the forces and movements between the holding rope 24 and the actuating rope 44 is necessary, particularly due to a so-called direction of lay in the case of coiled ropes, in order that the torques in the individual ropes and thus the torques of the suspended rope grab 30 about its longitudinal axis are controlled such that a desired rotation of the rope grab 30 only occurs if this is required for construction progress.

[0045] According to the invention, forces in the holding rope 24 and the actuating rope 44 are detected by way of corresponding detection means that can be arranged e.g. on the rope winches 21, 22 or on the deflection pulleys on the head 20 of the boom arm 18. By way of a control means, which is preferably arranged in the operator's cabin 17 on the carrier implement 12, the winches 21, 22 can be activated depending on the detected rope forces such that either a stabilization of the rotational position of the rope grab 30 about its longitudinal axis or a targeted turning desired by the machine operator is achieved. All that is required on the part of the machine operator is a corresponding input relating to a possibly desired compensation mode for positional stabilization or an input relating to a desired rotational position of the rope grab 30. Based on this 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, control of a rope grab 30 of simple construction is facilitated and made easier to a considerable degree for a machine operator.