Load gripper for intervention at a bore in the load

Abstract

An arrangement consisting of a load gripper (3) and a clamping device (10), wherein the load gripper (3) is designed for engagement with a bore (2) in a load (1), and has a load-bearing eye (4), a spreading body (5) and several spreading legs (6), wherein the spreading legs (6) extend between the spreading body (5) and the cylindrical surface of the bore (2), and the surface of the spreading legs (6) facing the cylindrical surface of the bore has a toothed joint, wherein the spreading legs (6) can be clamped to the cylindrical surface of the bore (6) by axial relative displacement of the spreading body (5) in the direction out of the bore (2), characterized in that the clamping device (10) has a wedge extension (11) and a drive device by which the wedge extension (11) can be driven into a gap (12) normal to the axis of the bore (2),by its expansion the spreading body (5) can be forcibly driven to move out of the bore (2) in the load.

Description

[0001] The invention relates to an arrangement consisting of a load gripper and a clamping device.

[0002] AT 518242 B1 shows a load gripper for engaging a bore in the load. The load gripper has a central, typically frustoconical, spreading body and several spreading legs (wedge-like parts) arranged side by side around the circumference of the spreading body. The radially outer surfaces of the spreading legs, relative to the longitudinal axis of the spreading body, are designed as toothed partial surfaces of a circular cylindrical surface. When the spreading body is moved parallel to its axis relative to the spreading legs in the direction where its small end face is at the front, the spreading legs are pushed radially away from the axis of the spreading body by the cylindrical surface of the spreading body.The spreader body is connected via a connecting rod, which runs away from the smaller, upper end face of the spreader body, to a load-bearing eye, i.e. a typically metallic part which has a through hole for the passage of a rope, shackle or load hook.

[0003] In the typical anchoring process of a load grab to a load, the grab is inserted into a hole in the load with the end facing away from the lifting eye first, so that the spreader body and the spreading legs, which are at the same height relative to its axis, are located in the hole, and the axis of the spreader body and the axis of the hole are essentially coaxial. As soon as the lifting eye is pulled away from the load – typically by a crane hook engaged with the load-bearing eye – the spreader body is pulled slightly towards the opening of the hole. The spreading legs, however, are slowed by friction against the outer surface of the hole and are thus prevented from also being moved towards the opening of the hole.This creates a relative movement between the spreader body and the spreader legs, causing the spreader legs to be pressed radially outwards against the bore's outer surface with respect to the bore axis, thus locking into place. As the crane hook continues to move upwards, the spreader leg carries the spreader bodies along with it, and the load is lifted using these.

[0004] To release the load gripper from the load, the lifting eye must be relieved of tension. In most cases, applying pressure or striking the lifting eye towards the load pushes the expanding body into the hole in the load. This gives the expanding legs radial inwards movement within the hole, releasing the clamping force on the outer surface of the hole. By then pulling on the expanding legs, bypassing the expanding body, towards the opening of the hole in the load, the expanding legs, and with them the entire load gripper, are moved out of the hole.

[0005] Documents DE 10065080 A1, US 1048585 A, DE 29913371 U1, US 3794369 A and US 4068879 A describe older, comparable devices. These devices are supplemented by additional components such as manually operated levers and pre-tensioned springs, which enable axial relative movement between the spreading body and the spreading legs to facilitate the processes of clamping and releasing the load gripper.

[0006] Although, with correct construction and use of the load grab known from AT 518242 B1, there has been no failure of the anchoring of the spreader legs to the walls of the bore in the load, concerns arise at least occasionally as to whether the connection between the spreader legs and the walls of the bore in the load is really sufficiently secure, since at the beginning of lifting operations there is no positive locking between the spreader legs of the load grab and the load.These doubts can only be unsatisfactorily resolved with the designs described in the aforementioned documents DE 10065080 A1, US 1048585 A, DE 29913371 U1, US 3794369 A, and US 4068879 A. This is because these designs make it possible, with significant drawbacks, to achieve a sufficiently high contact force between the spreading arms and the bore's outer surface before the actual load is applied by a crane. This is necessary to ensure that the teeth of the spreading arms penetrate the material deeply enough to create a satisfactory form fit. A further disadvantage of these designs is that it is not possible to retrofit existing load grabs with the necessary additional components.

[0007] The object of the present invention is to improve the design of load grippers known from AT 518242 B1 in such a way as to objectively increase safety against failure of the connection between the spreading legs and the walls of the bore in the load, thereby also eliminating the aforementioned doubts. The improvement can also be achieved by retrofitting existing load grippers.

[0008] To solve the problem, an arrangement according to claim 1 is proposed. The arrangement according to the claim is composed of a load gripper and a clamping device, or consists of the load gripper and the clamping device, wherein the load gripper is designed for engagement with a bore in a load, and has a load-bearing eyelet, a spreading body and several spreading legs, wherein the spreading legs extend between the spreading body and the cylindrical surface of the bore, and the surface of the spreading legs facing the cylindrical surface of the bore has a toothed joint, wherein the spreading legs can be clamped to the cylindrical surface of the bore by axial relative displacement of the spreading body in the direction out of the bore.

[0009] According to the invention, it is proposed to use a clamping device in addition to the load gripper, which has a wedge extension and a drive device, by which the wedge extension can be driven into a gap normal to the axis of the bore in the load, by widening the gap the spreading body can be driven to move out of the bore in the load.

[0010] This makes it possible, with the aid of the clamping device, to apply a force to the spreading legs even before the actual load gripper is loaded by the pulling force of a crane, which causes the tooth tips of their toothed partial surfaces to be pressed so strongly against the outer surface of the bore 6 that they penetrate significantly into the material of the load, so that the axial sliding out of the spreading legs from the bore is blocked by positive locking alone, regardless of the frictional fit already present.

[0011] The invention is illustrated by means of drawings. Fig. Figure 1 shows in a partial lateral sectional view an exemplary load gripper according to the prior art, which can be combined with the clamping device provided according to the invention to form an assembly according to the invention. Fig. 2: shows in a partial lateral sectional view an assembly according to the invention, consisting of a load gripper of Fig. 1 identical load gripper and a clamping device.

[0012] For the sake of clarity and ease of understanding, it is assumed for the purposes of the following description and the patent claims that the bore in the load, into which the load gripper engages, projects into the load from above. It should be clarified that this definition serves only for clarity and ease of understanding, and that the invention is also applicable and the patent claims also apply if the load gripper designed according to the invention is intended to pull in a direction other than away from the Earth's center, and if, for this purpose, the direction pointing outwards from the bore is horizontal or downwards.

[0013] Fig. Figure 1 shows a load 1 which has a vertically downward directed bore 2 with a circular cross-sectional area and a load gripper 3 comprising several individual parts, which projects into the bore 2 with one part and rests on the surface of the load 1 surrounding the bore 2 from above with another part.

[0014] The load gripper 3 includes (among other things) a load-bearing eye 4, a spreader body 5, spreader legs 6, a so-called lifting part 7 and a so-called release part 8.

[0015] The load-bearing eye 4 and the lifting element 7 are tensile-resistant to the spreading body 5 for forces in the direction parallel to the axis 9 of the spreading body 5. When the load gripper 3 is attached to the load 1 as intended, the spreading body 5 is located deep in the bore 2 and the axis of the spreading body 5 coincides at least approximately with the axis 9 of the bore 2.

[0016] The spreading legs 6 rest against the outer surface of the upwardly tapered outer surface of the spreading body 5. The tensile force applied upwards to the load-bearing eye 4 is transferred to the spreading body 5, which is rigidly connected to the load-bearing eye. As soon as the spreading body is lifted slightly due to the tensile force, it presses the spreading legs 6 radially outwards against the outer surface of the bore 2. This causes the spreading legs 6, with their serrated outer surfaces, to grip the outer surface of the bore 2 and the load 1. With further lifting of the load-bearing eye 4, the spreading legs 6 and the load 1, now rigidly connected to them, are moved upwards as well.

[0017] The release part 8 of the exemplary load cell 3 has a surface area against the spreading legs 6 from above, and the release part 8 is movable upwards relative to the spreading body 5. This ensures that when the load is applied to the in Fig. In the position shown in 1, no upward force is applied to the load-bearing eye 4, but rather to the release part 8, no jamming of the spreading legs between the spreading body 5 and the outer surface of the bore 2 occurs, but instead the entire load gripper 2 is moved upwards relative to the load 1 and is finally completely released from the load 1.

[0018] In Fig. Figure 2 shows how an exemplary clamping device 10 provided according to the invention and the load gripper 3 interact on the load 1.

[0019] The contact surface of the spreading legs 6, which rests against the outer surface of the bore 2, is designed as a toothed surface, so that tooth tips protrude from the spreading legs 6 towards the outer surface of the bore 2.

[0020] The general rule states that, for intended use, a wedge extension 11 is driven into a gap 12 perpendicular to the axis 9 of the bore 2, thus widening the gap and forcibly driving the spreader 5 out of the bore 2. This movement presses the spreader legs 6 against the outer surface of the bore 2, so that the tips of the teeth on the spreader legs 6 are pressed into the material of the load 1 on the outer surface of the bore 2. This creates a positive locking block against movement of the spreader legs 6 parallel to the axis of the bore 3 out of the bore even before the pulling force of a crane is applied to the load-bearing eye 4 – a block that remains in place continuously throughout the application of the crane's pulling force.

[0021] According to the optional advantageous embodiment shown, the flank of the gap 12 facing away from the bore 2 is a surface of the lifting part 7, and the flank of the gap facing the bore 2 is a surface of the releasing part 8.

[0022] According to the optional advantageous embodiment shown, the exemplary clamping device 10 comprises an annular base body 13, a wedge-shaped extension 11 monolithically connected to the base body 13, and a screw 14 which engages in a threaded nut in the annular base body 13. The wedge-shaped extension 11 projects radially inwards from one side of the inner surface of the annular base body 13, and the screw 14 penetrates the annular base body 13 radially on the side radially opposite the wedge-shaped extension 11.

[0023] The clamping device 10 is first positioned on the load gripper 3 such that the annular base body 13 surrounds the lifting part 7 and part of the release part 8, and the wedge extension 11 projects with its tip into the outer area of ​​the gap 12. To drive the wedge extension 11 further into the gap 12 in order to widen it, the screw 14 is turned so that it moves translationally radially inwards with respect to the axis 9 of the bore 2 in the load 1, pressing its front end face against the outer surface of the release part 8. Further turning of the screw causes the annular base body 13, and with it the wedge extension 11, to be displaced perpendicular to the axis 9 relative to the release part 8 and the lifting part 7 in the direction in which the tip of the wedge extension 11 points.The driving means for the movement of the wedge process mentioned above is in this case formed by the screw 14 in combination with the ring-shaped base body 13 and the release part 8.

[0024] The depicted embodiment is exemplary. Within the scope of the invention, numerous modifications are possible in the course of professional practice. The following approaches are listed as examples, without claiming to be exhaustive: The effect according to the invention can also be achieved, for example, by modifying the load gripper so that the gap into which the wedge extension must be driven is formed between the lifting element – ​​which is tensilely connected to the spreading body 5 – and the surface of the load 1 next to the bore 2. However, it must be borne in mind that the wedge extension presses directly against the surface of the load, creating a depression there, unless a protective intermediate layer is used.

[0025] The ring-shaped base body could also be designed in the manner of a pipe clamp, so that it is a ring-shaped structure whose diameter can be reduced by tightening a screw connection.

[0026] Instead of a ring-shaped base body, a pincer-like assembly could also be used, with the wedge-shaped extension protruding from one jaw towards the other jaw.

[0027] Instead of the pliers-like assembly, an assembly similar to a screw clamp could also be used, wherein the wedge-shaped extension protrudes from one of the two contact surfaces of the screw clamp towards the other contact surface.

Claims

[1] An arrangement consisting of a load gripper (3) and a clamping device (10), wherein the load gripper (3) is designed for engagement at a bore (2) in a load (1), and has a load receiving eye (4), a spreading body (5) and several spreading legs (6), wherein the spreading legs (6) extend between the spreading body (5) and the cylindrical surface of the bore (2), and the surface of the spreading legs (6) facing the cylindrical surface of the bore has a toothed joint, wherein the spreading legs (6) can be clamped to the cylindrical surface of the bore (6) by axial relative displacement of the spreading body (5) in the direction out of the bore (2), characterized by, that the clamping device (10) has a wedge extension (11) and a drive device by which the wedge extension (11) can be driven into a gap (12) normal to the axis of the bore (2), by widening the gap the spreading body (5) can be forced to move out of the bore (2) under the load. [2] Arrangement according to claim 1, characterized by , that the clamping device comprises an annular base body (13) and a screw (14), and that the wedge extension (11) projects radially inwards from one side of the inner surface of the annular base body (13). [3] Arrangement according to claim 2, characterized by , that by turning the screw (14) the circumference of the annular base body (13) can be reduced, and / or that by turning the screw the annular base body can be displaced normal to the axis of the spreading body (5). [4] Arrangement according to any one of claims 1 to 3, characterized by, that the flank of the gap (12) facing away from the bore (2) in its axial direction is a surface of a lifting element (7), wherein the lifting element (7) is tensilely connected to the spreading element (5) for forces in the direction parallel to the axis of the spreading element (5). [5] Arrangement according to claim 4, characterized by , that the flank of the gap (12) facing the axial direction of the bore (2) is a surface of a release part (8), wherein the spreading legs (6) bear against the release part from above with a surface portion, and the release part (8) is movable upwards relative to the spreading body (5). [6] Arrangement according to claim 4, characterized by , that the flank of the gap (12) facing the axial direction of the bore (2) is a surface of the load (1) lying outside the bore (2).

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