WO2010015871A2

WO2010015871A2 - Gripping device

Info

Publication number: WO2010015871A2
Application number: PCT/HU2009/000074
Authority: WO
Inventors: Attila Nagy
Original assignee: Fémtechnika Kft
Priority date: 2008-08-05
Filing date: 2009-08-05
Publication date: 2010-02-11
Also published as: WO2010015871A3; HU0800497D0; HUP0800497A2

Abstract

The invention relates to a gripping device, comprising a body (4) with receiving means (5) for connecting a force generator (3); a plurality of movable arms (2), each arm comprising a claw (10) and being pivotably fixed to the body (4); a first operating range (15) in which the claws (10) are directed inwards towards the centre axis (11) and a second operating range (16) in which the claws (10) are directed outwards from the centre axis (11). The arms are moved from the first (15) to the second operating range (16) by rotating each arm around a pivot axis (7) without removing the arms (2) from the body (4). The advantage of the invention is that it is easy and reliable to use and is adapted to grip different sizes of circular parts both from the outside and from the inside.

Description

Gripping device

TECHNICAL FIELD

The present invention relates to a gripping device for disassembling parts. This gripping device is especially advantageous for the removal of radial bearings, but is also well adapted for the removal of sleeves, bushings, etc. The gripping device is adapted for gripping the part to remove from either the outside or the inside.

BACKGROUND ART

In mechanical designs, there is a need to fasten parts to one another. Some parts, such as bearings, sleeves, bushings and the like are often attached to one another by press fit. Since the purpose of using press fit is to fix the parts together securely, the removal of such a part may prove to be cumbersome.

Some parts are attached to the outside of a corresponding part, e.g. a bearing on an axle, which means that if the bearing is to be removed, the removal tool must grip the bearing from the outside of the bearing. Similarly, some parts are attached to the inside of a corresponding part, e.g. a bearing in a hollow axle, which means that if the bearing is to be removed, the removal tool must grip the bearing from the inside of the bearing.

Different devices for the removal of such parts have been suggested. Most types display three or more arms and may comprise means for fixing the arms radially before the pulling action starts. Some devices have removable arms that can be reversed in order to achieve inner gripping surfaces. The arms may also be exchanged to other, specially adapted arms with inner gripping surfaces. US 5557833 describes a pulling device in which the gripping arms must be disconnected, reversed, and then reconnected in order to change the removal configuration from an outer to an inner pulling grip. The device also comprises a fixing means for fixing the arms radially before the pulling action starts.

US 5735033 describes a pulling device in which the gripping arms are provided with one end portion adapted for an outer removal action and one end portion adapted for an inner removal action. To change the removal configuration from an outer to an inner pulling grip, the arms must be disconnected, reversed, and then reconnected again. The centre of the arms may be mounted to the device in different positions.

US 1429567, US 2755540, US 3990139 and US 4694569 describes different pulling devices adapted for an inner pulling action wherein the gripping surfaces are brought into the gripping position and held in place by a first rotational action. The part to remove is then removed by a second rotational action.

None of the above documents discloses a combination internal and external puller device, that can easily be used both for the internal and external removal of parts.

DISCLOSURE OF INVENTION

An object of the invention is therefore to provide an improved gripping device adapted for both internal and external pulling actions, wherein the change from one pulling configuration to the other can be realized without removing the gripping arms.

Another object of the invention is to provide an improved gripping device that is adapted for the removal of parts with different inner and outer diameters. A further object of the invention is to provide an improved gripping device that adapts itself automatically to parts with different inner and outer diameters.

A further object of the invention is also to provide a gripping device with an improved design containing fewer parts.

These objects are attained according to the invention by not needing to remove the arms of the gripping device but by reversing them in a straightforward manner when changing the removal configuration between internal and external pulling actions. These objects are further attained according to the characterizing part of claim 1. The other claims contain advantageous embodiments and further developments of the gripping device according to the invention.

With a gripping device, comprising a body suitably with a receiving means for the connection of a force generator, said gripping device comprising a plurality of movable arms, each arm comprising a claw and being pivotably fixed to the body at a pivot axis, the object of the invention is achieved in that the gripping device also comprises a first operating range in which the claws are directed inwards towards a centre axis and a second operating range in which the claws are directed outwards from the centre axis and that the arms are moved from the first to the second operating range by rotating each arm around the pivot axis without removing the arms from the body.

By this first embodiment of the gripping device according to the invention, a gripping device is obtained which can be used both for the internal and external removal of parts with different inner and outer diameters respectively. The parts to be removed could be bearings but other parts are also conceivable. The gripping device can be changed from an internal removal condition to an external removal condition without having to dismount the arms of the device. This allows for a gripping device that is easy and efficient to use, both for the internal and external removal of parts.

In the first embodiment, the gripping device suitably comprises a tnreaded spindle as the force generator. The spindle is then mounted in a centre tapped hole in the body. The advantage of this is that the gripping device is self-contained and easy to use, which enables an easy and simple removal of the part to remove. This is advantageous for smaller workshops with occasional removal of parts.

In an advantageous further development of the gripping device according to the invention, the force generator may be e.g. a slide hammer or a hydraulic ram. This enables efficient removal of the part to remove. This is especially advantageous in larger workshops where many parts have to be removed.

In an advantageous further development of the gripping device according to the invention, the arms are spring-loaded in order to push the arms of the gripping device towards the part to remove. This improves the safety and ease of use.

In an advantageous further development of the gripping device according to the invention, the same spring pushes the arms towards the part to remove both when removing parts from the outside and the inside. This enhances the safety of the gripping device even further.

In an advantageous further development of the gripping device according to the invention, the spring is substantially enclosed in a space between the arm and the body. This improves the ease of use still further since the spring is enclosed within the gripping device.

In an advantageous further development of the gripping device according to the invention, the spring encircles the end portion of the body. This also improves the ease of use. In an advantageous further development of the gripping device according to the invention, the spindle of the gripping device comprises a conical disc adapted to push the arms towards the part to remove during an internal removal. This further enhances the safety of the gripping device.

In an advantageous further development of the gripping device according to the invention, the spindle is double-sided and symmetrical. This improves the ease of use in that the spindle does not have to be reversed when the arms are moved from one pulling configuration to the other.

In an advantageous further development of the gripping device according to the invention, the gripping device comprises a stop pin that limits the travel of an arm. This improves the safety of the gripping device still further.

In an advantageous further development of the gripping device according to the invention, the gripping device is combined with a slide hammer to form an extractor tool.

BRIEF DESCRIPTION OF DRAWINGS

The invention will be described in greater detail in the following, with reference to the embodiments that are shown in the attached drawings, in which

Fig. 1 shows a full side view of a gripping device according to the invention in the first operating range,

Fig. 2 shows a full side view of a gripping device according to the invention when removing a bearing from the outside,

Fig. 3 shows a full side view of a gripping device according to the invention when removing a bearing from the inside,

Fig. 4 shows a second embodiment of the gripping device according to the invention in a first gripping position, Fig. 5 shows a detailed cross-section of the pivot axis of the embodiment in fig. 1 ,

Fig. 6 shows a detailed cross-section of a second embodiment of the pivot axis of the embodiment in fig. 1 ,

Fig. 7a-c shows different embodiments of a spindle,

Fig. 8 shows an embodiment with an encircling spring,

Fig. 9 shows an embodiment with stop pins,

Fig. 10 shows an embodiment with a slide hammer as a force generator, and

Fig. 11 shows a detail of the embodiment in Fig. 10.

MODES FOR CARRYING OUT THE INVENTION

The embodiments of the invention with further developments described in the following are to be regarded only as examples and are in no way to limit the scope of the protection provided by the patent claims.

In the following, a radial bearing is used as an example of a part that is to be removed with the inventive gripping device. The radial bearing consists of an outer ring, a plurality of rolling elements, such as balls, cylindrical rollers, needle rollers, tapered rollers or spherical rollers, and an inner ring. The gripping device is adapted to extract the complete bearing by the outer ring or the inner ring, depending on the mounting of the bearing. The gripping device is also suitable to extract other similar parts, such as different types of bearings, sleeves, gears, inner or outer rings and other types of parts where it is possible to apply the gripping device on the outer edges or through the centre hole of the part in question. The gripping device is also adapted to grip the inner part of an outer ring of e.g. a broken bearing or a splitable bearing, i.e. a bearing where the inner ring and the rolling elements are removed, that is mounted in a housing. Further, the gripping device is also adapted to grip the outer part of an inner ring of e.g. a broken bearing or a splitable bearing, i.e. a bearing where the outer ring and the rolling elements are removed, mounted on an axle.

Fig. 1 shows a first embodiment of the inventive gripping device. The gripping device 1 comprises a force generator in the form of a spindle 3 having a thread with a pitch suitable for the removal of parts, preferably a thread with a low pitch. The head 20 of the spindle comprises a grip in order to provide means for forcible rotation of the spindle. Further, the gripping device comprises a body 4 with a centre tapped hole 5, where the thread is adapted to fit the thread of the spindle 3. The gripping device also comprises a plurality of arms 2, each arm having a first end 26 and a second end 27. The body 4 constitutes a rigid member that may be bar- like with a rectangular cross section for a device with two arms. For a device with three arms, the body may have a somewhat triangular shape. For a device with four arms, the body may have a somewhat cross or X shape. The body comprises two or more protruding portions with outer ends to which the arms are attached. The portions protrude symmetrically from the body with respect to each other. Thus, the angle between the portions on a body with two arms is 180 degrees and the angle between the portions on a body with three arms is 120 degrees. Fig. 4 shows an embodiment with a device comprising three arms. In this way, an even load on the device is guaranteed. A gripping device comprising more than three arms is also envisaged. In such an embodiment, a symmetric spacing of the arms with respect to each other is also advantageous.

At each end of a body portion, an arm 2 is attached. In the following, only one arm will be described. Since the device and thus the body is symmetrical, the same will apply for the other arm or arms attached to the body. The first end 26 of the arm is attached to the outer end of the body portion around the pivot axis 7 of the device. The arm 2 can be rotated around this pivot axis 7 without the need to remove the arm from the body. The arm is advantageously attached to the body by a pin 22 or the like, but it would also be possible to attach the arm with a removable fastener, e.g. a threaded fastener such as a screw or a bolt, should there be a need to replace the arm in an easy manner. The arm 2 is provided with a claw 10 at the second end 27. The claw has a gripping surface 14 adapted to bear on the part to be removed. The gripping surface may be provided with a rough surface of some kind to increase the friction between the claw and the part to be removed.

The gripping device can be used to remove parts that may be gripped from either the outside or the inside. A removal action in which a part to remove is gripped from the outside will be referred to as an outer or external removal, and a removal action in which the part to remove is gripped from the inside will be referred to as an inner or internal removal. The arms can thus be used in a first operating range 15 in which the claws 10 are directed inwards towards the centre axis 11 and in a second operating range 16 in which the claws 10 are directed outwards from the centre axis 11.

In the first operating range 15, shown in Fig. 2, the arms 2 are positioned around the outer ring of the bearing and are then rotated inwardly so that the claws 10 bear on the bearing. The spindle 3 is then rotated clockwise so that it bears on an axle or the like on which the bearing is fastened. By a continued rotation of the spindle, the device will pull the bearing from the axle or the like. It is also possible to use a slide hammer instead of rotating the spindle. The slide hammer is then fastened to the end of the spindle, directly in the centre tapped hole 5, or fastened by some other means directly or indirectly to the body 4 and then, by a repeatedly hammering action, the bearing is knocked off. This removing action resembles the one used with known external pulling devices and is not explained further. In the second operating range 16, shown in Fig. 3, the arms 2 are positioned inside the inner ring of the bearing and are then rotated outwardly so that the claws bear on the bearing. Normally, there is no counterpart to support the spindle when removing a part from the inside. If a counterpart is present, e.g. as in the case of a bearing mounted in a blind housing, the spindle 3 is rotated clockwise so that it bears on the counterpart. By a continued rotation of the spindle, the device will pull off the bearing. If there is no counterpart, a bridge of some kind could be used to support the spindle during removal. Normally, a force generator in the form of e.g. a slide hammer or a hydraulic ram (not shown) is used when removing parts from the inside. The slide hammer is fastened either to the body 4 directly or to the end of the spindle 3, e.g. by a tapped adaptor that is screwed on the spindle 3 and then, by a repeatedly hammering action, the bearing is knocked off. This removing action resembles the one used with known internal pulling devices and is not explained further.

The gripping device can be used together with different force generators, such as an internal force generator in the form of a spindle, where the force generator is substantially located at a first side of the body, being the side at which the arms are positioned for gripping. The gripping device can also be used together with an external force generator such as e.g. a slide hammer or a hydraulic ram, where the force generator is substantially located at a second side of body, being the side opposite to the first side. When an external force generator is used, it may be attached directly to the body or to the spindle itself. The attachment of the force generator to the body may be done either with a threaded portion that is threaded into a tapped hole in the body. The attachment may also be done with the force generator gripping around the body, preferably using pre-positioned indents or the like. The spindle 3 comprises in a first embodiment, shown in Fig. 7a, a head 20 to be used with a spanner or the like. The head is preferably provided with a hexagonal grip with collar, but also a grip such as tone or the like is feasible. The head further comprises a receiving area 21 adapted for an easy attachment of an external force generator, such as a slide hammer. The spindle 3 is preferably threaded with a low-pitch thread. The tip of the spindle is adapted to rotate easily when it bears on a counterpart such as an axle or the like. In this embodiment, the tip of the spindle is provided with a ball that is rotatably mounted in a hole in the tip. In this way, the friction between the tip of the spindle and the counterpart will be reduced. This will lessen the wear of the spindle.

In another embodiment, shown in Fig. 7b, the spindle is provided with a conical disc 19 at the head. The conical disc 19 may be integrally manufactured with the spindle 3 or may be mounted separately. In the shown embodiment, the conical disc 19 replaces the head and is thus provided with a suitable internal grip 28 instead, in order to be able to rotate the spindle during outer removal. The internal grip 28 may be e.g. a hexagonal grip, a torx or the like. The conical disc 19 may in another embodiment comprise a separate part that is attached to the head in a suitable way. The conical disc 19 may e.g. be attached to the head 20 by a clamping action or it may be provided with a thread that fits the spindle. The purpose of the conical disc is to fixate the arms during an internal removal. When the claws have been properly positioned through the part to remove, the arms may be forced outwards by turning the spindle so that the lateral outer surface of the conical disc bears on the arms. This will push the arms and claws towards the part to remove, which allows for a safe removal of the part.

In another embodiment, shown in fig. 7c, the spindle is symmetrical. This may be advantageous when there is a possibility for the spindle to bear on a counterpart when the device is used for internal removal. By using a symmetric spindle, there is no need to remove the spindle in order to change the direction in which the tip of the spindle points. This may be the case e.g. when removing inner rings with a large diameter. The counterpart may then be a part of the machine from which the inner ring is to be removed or it could be a removable counterpart such as a bridge or the like. The spindle can in this embodiment comprise two hexagonal heads 20 and each head can comprise an inserted ball, as in the tip described above, for friction reduction. Other types of spindles are also possible.

Fig. 5 shows a cross-section of the pivot axis 7. The outer member of the body comprises a hole 13. The first end 26 of the arm 2, the hinge end, is divided into two flanges with an enclosed space 12 in between. The flanges reach around the body of the device. The flanges are provided with holes corresponding to hole 13 when the arm 2 is mounted to the body 4. A pin 22 is inserted through the holes, fixing the arm to the body. The holes in the flanges are suitably slightly smaller than the pin so that a press-fit is achieved. The hole 13 in the body is suitably slightly larger than the pin 22, thereby allowing the arm to rotate around the pivot axis 7. The pivot axis 7 is preferably translated a predetermined distance from the centre axis 11. The pivot axis 7 is further preferably located in a plane, which plane is perpendicular to the centre axis 11 and to a centreline of the body 4, which centreline is perpendicular to the centre axis 11.

In a preferred embodiment, each arm is provided with a spring 6. The purpose of the spring is to preload the arms in the gripping direction so that the arms are forced towards the part to be removed. This helps the arms to maintain their gripping position, and reduces the risk of slippage during the removal of a part. This will lessen the risk of damaging the part or the device during a removal and will also enhance the security for the user of the device. The spring will bear on a contact surface of the body. A first contact surface 8 is provided on the lower side of the body 4 and a second contact surface 9 is provided on the upper side of the body 4. The spring 6 is mounted in the enclosed space 12 and will bear on the first contact surface 8 when the device is in the first operating range 15 and on the second contact surface 9 when the device is in the second operating range 16.

In Fig. 5, the device is in the first operating range. The spring 6 thus bears on the first contact surface 8. The angle between the contact surface and the corresponding bearing surface of the spring is selected in order to achieve a suitable preload force. In the shown embodiment, the contact surface 8 and the corresponding bearing surface of the unloaded spring are parallel when the arm is in its innermost position.

The spring 6 shown in Fig. 5 is a bent plate spring. The spring is bent in a Z-shape with a perpendicular attachment part, by which the spring is attached to the arm with a screw. In this way, it is possible to provide a large enough preload force of the spring and at the same time, the spring fits substantially in the enclosed space of the arm. When the arm is rotated to the second operating range, the spring is compressed and then again expands to bear on the second contact surface 9 for the second operating range 16. In the second operating range, the arms are preloaded so that the arms are pushed outwards, away from the centre axis 11. The advantage of having the spring enclosed in the enclosed space 12 is that the spring will be enclosed for both internal and external removal. The spring will thus not be in the way or stick out in either operating range.

In Fig. 6, an alternative embodiment of a spring 6 is shown. In this embodiment, a spiral spring is used. The spring is inserted in a cavity 23 in the arm. The bearing surface of the spring is preferably flat in order to facilitate a smooth action of the device. The end surface 24 of the body, perpendicular to both the first 8 and the second 9 contact surface, may be flat as is shown in Fig. 5. This creates a third contact surface on which the spring may bear. This may be advantageous e.g. during assembly or for the transportation of the device. It is also possible for the end surface 24 of the body to have a curved shape, as shown in Fig. 6, to enable easy rotation of the arm from the first 15 to the second operating range 16.

In a further embodiment shown in Fig. 8, an encircling spring 25 is used to pre-load an arm in the gripping direction so that the arm is forced towards the part to be removed. The spring encircles the whole end portion of the body and is mounted to the body with a fastening means. The spring is preferably made from a bent plate spring. By using an encircling spring in this way, the spring is fixed to the body but can still be used to preload the arm both for internal and external removal. The shape of the spring is adapted to create the desired pre-load force for both internal and external removal. In this embodiment, it is also possible to provide different preload forces in the first and second operating ranges.

The design of the gripping device determines the operating range of the device, i.e. the dimensions that the gripping device is adapted for. In one example, the extractor device is adapted for the internal removal of bearings with an inner ring diameter of between 12 to 80 mm and at the same time for the external removal of bearings with an outer diameter of 24 to 105 mm. Other ranges and sizes are conceivable. By using a plurality of gripping devices with different sizes, the complete need of a workshop can be provided for.

In order to prevent the gripping device being used outside its intended first or second operating range, a corresponding stop pin may be provided in the body. The stop pin is positioned in the outer end of each body portion, beyond each pivot axis with reference to the centre axis 11. Fig. 9 shows an embodiment with a first stop pin 17 intended to limit the travel of an arm outwards in the first operating range 15 and a second stop pin 18 intended to limit the travel of an arm outwards in the second operating range 16. When the arm is at its outermost permitted position, it will bear on the stop pin and cannot be moved any further without removing the pin. In this straightforward manner, it will be immediately clear to the user when the upper limit for a gripping device has been reached. Instead of unintentionally using the gripping device in an inadvisable way, the user can instead use a gripping device of the proper size.

To rotate an arm from one operating range to the other, the restriction of travel from the stop pin must be removed. This can be done by removing the pin itself or by using a spring-loaded pin that can be pushed into the housing so that it becomes level with the body housing.

It may be advantageous to provide each arm with a bend in the middle section of the arm. This may extend the reach of the claws of the arms. The bend angle α may advantageously be between 10 and 40 degrees, but other values may be used depending on the intended use of the device. The bend angle is adapted to the operating range so that it is ensured that the claws can get a good grip on the part to remove.

To facilitate the removal of a part to be removed, the gripping device may be connected to an external force generator, creating a complete extractor tool. The external force generator may be e.g. a slide hammer. The connection is made by means of an adaptor that is fastened to the spindle

3 or directly to the body 4. This can be done by providing e.g. an inner thread in the external force generator that is adapted to be mounted to the spindle of the gripping device. One embodiment of an advantageous slide hammer 33 is shown in Fig. 10, and in Fig. 11 a detailed cross-section of the slide hammer 33 is shown.

The slide hammer 33 is preferably, but not necessarily, used together with a conical disc 19. In the illustrated example, a separate conical disc 19 is shown, which can be attached to the head 20 of the spindle 3 when required. The slide hammer 33 comprises a tube 29, a weight 30, a striking surface 31 and a handle 32. When the gripping device 1 is positioned inside the part to be removed, the spindle with the conical disc is rotated clockwise so that the arms are forced outwards so that the lateral outer surface of the conical disc bears on the arms. This will push the arms and claws towards the part to remove and lock them in this position. Thereafter, the tube is attached to the spindle. The tube is provided with an internal thread and is screwed on to the spindle. The full length of the tube need not be provided with an internal thread. As shown in Fig. 11 , the lower part of the tube does not have an internal thread. By having an internal thread that is only as long as necessary to fixate the tube to the spindle, assembly time is saved. The tube may be manufactured in one piece or may consist of several sections. In one example, an unthreaded tube portion is one section and a threaded tube portion with the handle is one section. When the tube is screwed to the spindle, it will eventually bear on the body of the gripping device. This will then lock the spindle so that the spindle cannot rotate during removal of the part. This in turn fixates the arms, which allows for a safe removal of the part to be removed.

Another advantage of using a hollow tube with an internal thread is that the total length of the gripping device and slide hammer combination can be shorter, since the full length between the body of the gripping device and the handle of the sliding hammer can be used for the sliding weight. This allows for a compact extractor tool. When the tube is fixed to the spindle, the weight 30 is repeatedly struck towards the striking surface, thereby knocking the part loose.

Other external force generators may be used as well, e.g. hydraulic rams or hydraulic cylinders. The advantage with a slide hammer is that it does not need to bear on a surface on the structure in which the part to remove is positioned. When a large number of parts are to be removed, an automatic extractor tool may be advantageous. The removal action may be done either with a number of extraction blows, e.g. supplied with a slide hammer, or with a continuous movement, e.g. supplied by a hydraulic tool. The gripping device may also be used in combination with a hydraulic spindle.

The invention is not to be regarded as being limited to the embodiments described above, a number of additional variants and modifications being possible within the scope of the subsequent patent claims. The gripping device can, for example, also be adapted for the removal of parts with other outlines than circular, e.g. elliptic or regular shaped outlines such as rectangles, hexagonal shapes, etc.

Claims

1. Gripping device, comprising a body (4) and a plurality of movable arms (2), each arm comprising a claw (10) and being pivotably fixed to the body (4) at a pivot axis (7), characterized in that the gripping device comprises a first operating range (15) in which the claws (10) are directed inwards towards a centre axis (11) and a second operating range (16) in which the claws (10) are directed outwards from the centre axis (11) and that the arms are moved from the first (15) to the second operating range (16) by rotating each arm around the pivot axis (7) without removing the arms (2) from the body (4).

2. Gripping device according to claim 1, characterized in that the gripping device is provided with two arms (2).

3. Gripping device according to claim 1, characterized in that the gripping device is provided with three arms (2).

4. Gripping device according to claim 1, characterized in that the gripping device is provided with more than three arms (2).

5. Gripping device according to any of the preceding claims, characterized in that each arm (2) is forced inwards by a spring (6; 25) in the first operating range (15) and that each arm (2) is forced outwards by the same spring (6; 25) in the second operating range (16).

6. Gripping device according to claim 5, characterized in that the spring (6; 25) is positioned at the pivot axis (7).

7. Gripping device according to claim 5 or 6, ch aracterized i n that the spring is substantially enclosed in a space (12) between the arm (2) and the body (4).

8. Gripping device according to any of claims 5 to 7, cha racterized i n that the spring (6) constitutes a bent plate spring.

9. Gripping device according to any of claims 5 to 7, characterized in that the spring (6) constitutes a coil spring.

10. Gripping device according to claim 5 or 6, characterized in that the spring (25) encircles the end portion of the body (4) and is mounted to the body (4).

11. Gripping device according to any of the preceding claims, characterized in that the gripping device further comprises a receiving means for the connection of a force generator.

12. Gripping device according to claim 11, characterized in that the receiving means is a centre tapped hole (5).

13. Gripping device according to claim 11, characterized in that the receiving means comprises pre-positioned indents on the surface of the body (4).

14. Gripping device according to any one of claims 11 to 13, characterized in that the force generator is a slide hammer suitably connected to the body (4).

15. Gripping device according to any one of claims 11 to 13, characterized in that the force generator is an hydraulic force generator suitably connected to the body (4).

16. Gripping device according to claim 12, characterized in that the force generator is a threaded spindle (3) mounted in the centre tapped hole (5).

17. Gripping device according to claim 16, characterized in that the spindle (3) comprises a conical disc (19).

18. Gripping device according to claim 16 or 17, characterized in that the spindle (3) is double-sided and symmetrical.

19. Gripping device according to any of the preceding claims, characterized in that the body (4) comprises a stop pin

(17, 18) that limits the travel of an arm (2).

20. Gripping device according to any of the preceding claims, characterized in that each arm (2) is provided with a bend angle (α) of between 10 and 40 degrees.

21. Extractor tool comprising a gripping device according to any of claims 16 to 20 and further comprising a slide hammer (33), characterized in that the slide hammer (33) comprises an internal threaded tube (29), a weight (30) and a striking surface

(31).