Clamp system, gripping device therefore and method of using the clamp system

Abstract

In a clamp system for a slender object (16), such as a pile or pipe and the like, a clamp (1) and the object are to be applied around one another. The clamp has a frame (4) defining an axial direction. Furthermore, gripping devices (3) are provided which are spaced in circumferential direction of the frame (4). A stop (25) defines an end position of the gripping device (3), the gripping device (3) in gripping state and positioned in the end position prevents the object (16) from displacing with respect to the frame (4) in a first axial direction of the passage (9), in which first axial direction the gripping device (3) is held pressed against the stop (25), and the gripping device (3) allowing the object (16) to displace with respect to the frame in the second axial direction opposite the first axial direction.

Claims

1. A camp system for a slender object, such as a pile or pipe and the like, said clamp system comprising a frame defining a longitudinal axis, wherein the object and the frame are to be arranged around one another in such a way that the longitudinal axis of the frame is generally parallel to the longitudinal axis of the object, as well as clamping means for clamping the object with respect to the frame, wherein the clamping means comprise: at least one gripping device which is rotatably connected to the frame according to an axis of rotation which is oriented transversely with respect to the longitudinal axis of the frame, said gripping device having a gripping state for clamping said object with respect to the frame and an idle state, and at least one stop which defines an end position of the gripping device (3), said gripping device in gripping state and positioned in said end position preventing the object from displacing with respect to the frame in a first axial direction along the longitudinal axis of the frame, in which first axial direction the gripping device is held pressed against the stop, and said gripping device allowing the object to displace with respect to the frame in a second axial direction opposite the first axial direction, and further comprising a wedge type clamp comprising wedge assemblies associated with the frame for providing frictional engagement with said object as a result of a relative displacement of the wedge type clamp with respect to the object according to the longitudinal axis, wherein the gripping device is arranged with respect to the wedge assemblies in such a way that during said relative displacement of the object and the wedge type clamp of said gripping device is transferred from the gripping state, in which the object is held with respect to the frame by the gripping devices, into the idle state so as to establish said frictional engagement between the wedge assemblies and the object.

2. Clamp system according to claim 1, wherein a gripping device is mounted to the frame by means of a respective pivot and which gripping device is displaceable between an active position which is radially oriented with respect to the longitudinal axis of the frame and an inactive position slanted with respect to the radially oriented active position.

3. The clamp system according to claim 2, wherein the stop is provided on the frame and/or a base or mounting.

4. The clamp system according to claim 3, wherein a gripping device is biased toward the stop, such as by an elastic pretension.

5. The clamp system according to claim 1, for introduction in a hollow object, wherein the gripping device is carried out for gripping the internal surface of the hollow object.

6. The clamp system according to claim 1, wherein the frame delimits a passage for accommodating the object and the gripping device is carried out for gripping the external surface of the object.

7. The clamp system according to claim 6, wherein the frame comprises frame halves which are connected to each other through a hinge the hinge axis of which is generally parallel to the longitudinal axis of the frame, said frame halves being transferrable between an active position closed onto each other around the object, and an open position in which the frame can be positioned on the object.

8. The clamp system according to claim 7, wherein closure means are provided on the frame halves for holding said frame halves pressed onto each other respectively for giving said frame halves free.

9. The clamp system according to claim 1, wherein the gripping device is carried out for gripping the internal surface of the hollow object, and the wedge assemblies and gripping device are oriented outwardly with respect to the frame for engagement with the internal surface of the hollow object.

10. A method for lifting a hollow slender object by means of the clamp system according to claim 9, comprising the steps of: introducing the frame in the lying object, activating the wedge assemblies so as to engage the internal surface of the lying object, activating one or more gripping devices so as to grip the internal surface of the lying object, lifting the object gripped by the gripping device(s) and transferring said object towards an upright position, during the process of transferring the object to the upright position, displacing the object with respect to the frame so as to provide or increase frictional engagement between the wedge assemblies thereof and the object, and during the process of transferring the object to the upright position, transferring the gripping device(s) from the gripping state into the idle state.

11. The method according to claim 10, comprising the step of: during the process of transferring the object to the upright position, transferring one or more gripping devices from the gripping state into the idle state by making the gripping device(s) rotate about the respective tangentially oriented axis of rotation thereof.

12. The method according to claim 10, comprising the steps of: displacing the object with respect to the clamp under the influence of gravity as a result of transferring the object towards the upright position, during the step of displacing the object with respect to the wedge type clamp, pivoting the gripping device(s) out of the gripping position into the idle position.

13. The clamp system according to claim 1, wherein the frame delimits a passage for accommodating the object, the gripping device is carried out for gripping the external surface of the object, and the wedge assemblies and gripping device are oriented inwardly with respect to the frame for engagement with the external surface of the object.

14. The method for lifting a slender object by means of the clamp system according to claim 13, comprising the steps of: fitting the frame around a lying object, activating the wedge assemblies so as to engage the external surface of the lying object, activating one or more gripping devices so as to grip the external surface of the lying object, lifting the object gripped by the gripping device(s) and transferring said object towards an upright position, during the process of transferring the object to the upright position, displacing the object with respect to the frame so as to provide or increase frictional engagement between the wedge assemblies thereof and the object, and during the process of transferring the object to the upright position, transferring the gripping device(s) from the gripping state into the idle state.

15. The clamp system according to claim 1, wherein a gripping device (3) is positioned at a distance in axial direction from the wedge assemblies (11).

16. The clamp system according to claim 1, wherein a gripping device is pivotable out of the radial position in accordance with the direction of relative displacement of the object with respect to the frame which causes frictional engagement between the wedge assemblies and the frame.

17. The clamp system according to claim 1, wherein the frame has opposite axial ends and a gripping device is positioned on the end which faces in the clamping direction of the wedge assemblies.

18. Clamp system according to claim 1, wherein a plurality of gripping devices is provided, said gripping devices being spaced around, and being oriented transversally with respect to, the longitudinal axis of the frame.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will now be described further with reference to the embodiment of the clamp system as shown in the drawings.

(2) FIG. 1 shows a view in perspective from below on a first embodiment of the clamp system.

(3) FIG. 2 shows a view in perspective of a gripping device for the clamp system of FIG. 1.

(4) FIGS. 3-5 show several stages of the process of lifting and upending an object.

(5) FIG. 6 shows part of the clamp system of FIG. 1 as applied on a lying object as according to FIG. 3.

(6) FIG. 7 shows part of the clamp system of FIG. 1 as applied on an upended object as according to FIG. 5.

(7) FIG. 8 shows a partial view in longitudinal section of a second embodiment of the clamp system.

DETAILED DESCRIPTION

(8) The first embodiment of the clamp system as shown in FIG. 1 consists of the wedge type clamp which has generally been denoted by reference numeral 1, as well as the series 2 of gripping devices 3. The wedge type clamp 1 has an annular frame 4 which consists of two frame halves 5, 6 which are connected to each other through the hinge 7 and an actuator means 8 at one end. By energizing the actuator 8, the frame halves 5, 6 can be swung around the hinge 7 between an open position and the closed as shown. In the open position, the frame halves can be located around an object which upon closure of the frame halves 5, 6 is then be accommodated within the internal space 9 of the frame 4. The clamp system can be lifted by means of the lugs 10, onto which hoisting cables of a crane and the like are to be mounted.

(9) Around the internal space 9 of the frame, several wedge assemblies 11 have been spaced. These wedge assemblies are shown in radial section in FIGS. 6 and 7, and consist in a known way of wedge parts 12, 13 which are slideable along each other according to the slanting surfaces 14. The inner wedge part 13 has a friction surface 15 which engages the external surface 30 of the object 16, as shown in FIGS. 3-7. The initial frictional engagement between the wedge assembly 11 and the object can be obtained by means of the wedge assembly actuator 26. In the upright position, the wedge assemblies 11 additionally clamp the object 16 securely in the internal space 9 of the wedge type clamp 1 under the influence of gravity, the clamp system itself being suspended from a crane and the like by hoisting cables 23 connected to the lugs 10 (only one of these being shown in FIG. 3).

(10) In a lying position of the object 16 as shown in FIG. 6, this clamping action of the wedge assemblies is limited, as gravity does not influence the position of the object 16 and the clamp system 1 with respect to each other. With the aim of still being able to lift the object from this lying position in a secure and reliable way, the series 2 of gripping devices 3 have been mounted on one axial end of the frame 4. These gripping devices 3 consist each of a piston/cylinder device 17 and the mounting plate 21. The housing 18 thereof is connected to the mounting plate 21 through the pivot 22, the pivot axis of which runs transverse with respect to the longitudinal axis of the piston/cylinder device 17. The piston 19 has a gripping surface 20 at its free end. By means of a spring member 24 which is slung around the housing 18 and both ends of which are connected to the mounting plate 21, the piston/cylinder device 17 is biased against said mounting plate 21 and is held under pretension against the stop face 25 thereof.

(11) After the clamp system 1 has been arranged around the object 16 by opening and subsequently closing the frame halves 5, 6, the gripping devices 3 are energized in such a way that the gripping surfaces 20 thereof are pressed onto the object. Thereby, a stable position of the object 16 with respect to the clamp system 1 is obtained. The spring members 24 are holding the piston/cylinder devices 3 in the clamping position, at right angles to the axis of the frame 4.

(12) As soon as the object is hoisted somewhat in this condition, it starts to tilt. Thereby, the force of gravity obtains a component which is directed along the longitudinal direction of the object and the axis of the frame. Initially, any movement of the object under the influence of this gravity force component with respect to the frame is prevented by the spring members 24 which hold the piston/cylinder devices in position against the corresponding stop faces 25. As soon as however the gravity force component in question surpasses a certain threshold, the spring elements 24 give way and the piston/cylinder devices start to rotate around the pivots 22. This makes that the wedge assemblies 11 start to exert a friction force on the object 16, in such a way that finally the full gravitational force acting on the object 16 is borne by said wedge assemblies. The gripping devices 3 then lie idle against the object 16, without having any effect anymore on the lifting of the object.

(13) FIGS. 3-5 show a particular lifting operation in which the clamp assembly may be used in a particular beneficial way. As shown, the object 11 has a lying or horizontal position. Near one of its ends, the clamp system 27 is positioned, a first hoisting cable 23 extending between the clamp system 27 and a double hoisting block 28 suspended from a crane (not shown). Furthermore, a second hoisting cable 29 extends between this double hoisting block 28 and the object 11, near the other end thereof.

(14) The force F as exerted by the first hoisting cable 23 on the clamp system 27 has a component F.sub.1 which is oriented according to the axis of the clamp system 27, and counter to the direction in which the wedge assemblies thereof would be activated. In such case, the clamping action exerted by the wedge assemblies on the object, as obtained after energizing the actuators thereof, appears to be insufficient to stabilize the clamp system 27 with respect to the object 11. However, by energizing the gripping devices 3 as described before, such stable position of the clamp system 27 can still be obtained. As the force component F.sub.1 causes the piston/cylinder devices 17 to be pressed firmly onto the corresponding stop faces 25, the stability of the clamp system 27 with respect to the object is furthermore ascertained.

(15) The embodiment of the clamp system described before is fit for accommodating an object within the internal space 9 thereof. As an alternative, the clamp system may be carried out for introduction in the hollow space of a hollow object, as shown in FIG. 8. In this case, both the wedge assemblies 11 and the gripping devices engage the inner surface 31 of the object 16. The way of handling this clamp system and object is however similar to the clamp system described before.

LIST OF REFERENCE NUMERALS

(16) 1. Wedge type clamp 2. Series of gripping devices 3. Gripping device 4. Frame 5., 6. Frame half 7. Hinge 8. Actuator frame 9. Internal space of frame 10. Lug 11. Wedge assembly 12., 13. Wedge part 14. Slanting surfaces 15. Friction surface of wedge assembly 16. Object 17. Piston/cylinder device 18. Cylinder 19. Piston 20. Pressure surface 21. Mounting plate 22. Pivot 23. Hoisting cable 24. Spring element 25. Stop face 26. Actuator wedge assembly 27. Clamp system 28. Double hoisting block 29. Hoisting cable 30. External surface object 31. Internal surface object