CN102216555A - Method for using retainer, and retainer - Google Patents

Abstract

The present invention relates to a method for using a retainer, and to a retainer. The holder (14) comprises a first clamping arm (18a) and a second clamping arm (18b) provided with clamping jaws (21a, 21b) for clamping a drill pipe (9), a rock bolt, etc. . The clamping arms are rotated relative to their pivot points (19a, 19b) by means of an actuator (20), whereby the clamping jaws move towards or away from each other. On the part between the pivot points of the clamping arms there is a shape member which interconnects the movements of the clamping arms so that they are interrelated and thus cause the clamping arms to move along the clamping The movement of both directions of the movement of the arm is synchronized.

Description

Method for using retainer and retainer

technical field

The invention relates to a method for moving a clamping arm belonging to a holder of an excavating device in such a way that the clamping jaws arranged in the clamping arm are simultaneously moved towards each other and the clamping jaws Drill rods, rock bolts or similar excavating tools are clamped between them in a drilling center of a rock drilling unit or in another excavating device. Mechanical synchronization is provided between the clamping arms so that their movements are related to each other.

The invention also relates to a holder suitable for a feed beam of a rock drilling unit, rock bolter or similar excavating equipment. The retainer includes at least two clamping jaws moved by one or more actuators. There is a synchronization mechanism between the clamping arms so that their movements are related to each other.

The field of the invention is described in more detail in the preambles of the independent claims.

Background technique

Rock drilling is performed using a rock drilling unit provided with a rock drilling machine and tools connected thereto to produce boreholes into the material to be worked on. A tool may comprise a drill rod and a drill bit connected to its distal end, or if a longer borehole is to be drilled, the tool may comprise a plurality of continuous drill rods connected back and forth into an extension rod arrangement. When starting to drill, the drill rod needs to be centered by guiding the drill rod by means of the clamping jaws of the holder located in the drilling center. Furthermore, the retainer may be used to lock the drill rod or other drilling tool against rotation, eg when the drill rods are attached to each other, to a drilling machine or a drill bit.

Publication US 4438984 discloses a retainer in which the clamping arms of the retainer are interconnected by rods that transmit force from one arm to the other. The disclosed structure takes up a lot of space on the feed beam.

Contents of the invention

It is an object of the present invention to provide a new and improved method for using a retainer and a retainer.

The method of the invention is characterized in that the clamping arm is provided with a shape member in the part between the pivot joints of the clamping arm, and by means of the shape member, the first clamping along the two directions of travel of the clamping arm The movement between the arm and the second clamping arm is synchronized.

The cage of the invention is characterized in that the synchronization means of the cage are arranged on the part between the first pivot joint and the second pivot joint; and the synchronization means comprise a shape member formed in the first clamping arm and a second clamping arm and are arranged to transmit synchronous movement between the clamping arms in both directions of travel of the clamping arms.

The idea of the invention is that the holder comprises synchronization means by which the movements of the clamping arms are correlated. The synchronization device is decoupled from one or more actuators acting on the clamping arm and transmits the movement of the clamping arm in both directions of travel of the clamping arm. The aforementioned synchronization means are realized by means of shape members arranged in the clamping arms on the part between the pivot joints of the clamping arms.

An advantage of the invention is that it does not in any way increase the external dimensions of the holder, since the synchronization device is arranged on the part between the pivot joints. A further advantage is that by using shaped surfaces formed in the clamping arms, synchronization can be achieved using a simple mechanical structure and a small number of components. Due to this synchronization, the weight of the cage does not increase significantly. Furthermore, the retainer is reliable in operation.

According to an embodiment, the shape members on the part between the pivot joints are in constant contact with each other and are therefore always ready to synchronize the movement of the clamping arms in both directions of travel.

According to an embodiment, the synchronization device comprises shaped surfaces formed directly in the structure of the first clamping arm and the second clamping arm, said surfaces being arranged opposite to each other and by their contact surfaces arranged opposite to each other in the clamping arms. transfer synchronous movement between them.

According to an embodiment, the first clamping arm and the second clamping arm are provided with compatible teeth arranged opposite each other, the movement between the clamping arms being transmitted by direct tooth contact. The teeth can be manufactured directly in the structure of the clamping arm.

According to an embodiment, the shape surfaces formed in the first clamping arm and the second clamping arm are in constant contact with each other at least over some part thereof.

According to an embodiment, the synchronization device comprises a shaped surface formed in the first clamping arm and the second clamping arm on a portion between the pivot joints. The shaped surfaces are interconnected by a link separate from the clamping arms and arranged opposite the shaped surfaces. However, the connection piece is not attached to the clamping arm and to a shape surface provided in the clamping arm. During synchronization, motion can occur between the shape surface and the connector.

According to an embodiment, the first clamping arm comprises at least two first connecting cams which are arranged at an axial distance from each other when viewing the holder in the direction of the center. Correspondingly, the second clamping arm comprises, on the part between the pivot joints, at least two second connecting cams arranged at an axial distance from each other. The first connecting cams and the second connecting cams are staggered on a portion between the pivot joints. Furthermore, the first connecting cam and the second connecting cam are provided with connecting slots which are open toward each other and which are arranged to coincide when viewed in the direction of the center, the connecting slots being Arranged to form a connecting channel when viewed in the direction of the center. The connecting channels are provided with connecting pins which serve as transfer members between the interleaved connecting cams. When the clamping arm moves, the connecting pin moves vertically. Vertical movement of the connecting pin is allowed by longitudinal holes or the like provided in the body of the holder. The connecting pin is a separate part that is not attached to the clamping arm.

According to an embodiment, the first clamping arm is provided with a non-movable connecting pin, the outer surface of which serves as the first shape surface. The second clamping arm comprises a longitudinal connection opening which serves as a second shaped surface. A connecting pin is arranged through the connecting opening, the shaped surface of the connecting pin and the connecting opening transmitting a synchronous movement between the clamping arms.

According to an embodiment, the holder comprises only a single actuator arranged between the clamping arms and connected to act on both clamping arms simultaneously.

According to an embodiment, the holder only comprises a single actuator arranged to act on the first clamping arm only. In this case, the movement to the second clamping arm is transmitted via the synchronization device.

According to an embodiment, the holder comprises at least two actuators, at least a first actuator being connected to act only on the first clamping arm, and at least one second actuator arranged to act only on the second clamping arm. Tight arms.

According to an embodiment, the actuator is a hydraulic cylinder pivotally connected to the clamping arm.

According to an embodiment, the actuator is arranged to direct the force required for moving the clamping arm directly to the clamping arm. This is advantageous for the durability of the construction.

According to an embodiment, the actuator is connected to the clamping arm by a pivot. The pivoting makes for a durable construction and, moreover, it can be used to reduce friction.

According to an embodiment, the actuator is a pressure medium cylinder arranged transversely with respect to the longitudinal axis of the clamping arm. Accordingly, the linear direction of travel of the actuator is arranged to substantially correspond to the direction of travel of the clamping jaws.

According to an embodiment, the actuator is placed outside the portion between the pivot points of the clamping arm. Thus, the fixed point at which the actuator is connected to the clamping arm can be located at a greater distance from the pivot point of the clamping arm, thus allowing a larger torque arm to be achieved and thus increasing the clamping force generated by the actuator.

According to an embodiment, the clamping jaws comprise, on their surfaces facing each other, slots with a substantially V-shaped cross-section, thus allowing the clamping jaws to center a drill rod or the like compressed therebetween. Also due to the shape of the jaws, it is also possible to center drill rods etc. with different diameters.

According to an embodiment, the clamping jaws are arranged to move at the same travel speed, over the same distance and symmetrically with respect to each other.

Description of drawings

Some embodiments of the invention will be described in more detail with reference to the accompanying drawings, in which:

Figure 1 is a schematic side view of a rock drilling machine provided with a boom and a drilling unit and a second excavating device arranged thereon;

Figure 2 is a schematic perspective view of the drilling unit;

Figure 3 is a schematic view of the retainer of the present invention seen from the direction of the front end of the feed beam;

Figure 4 is a schematic perspective view of the holder of Figure 3 without the body plate;

Figure 5 is a schematic sectional view along line E-E of the retainer of Figure 2;

Figure 6 is a schematic cross-sectional view along line D-D of the retainer of Figure 2;

Figure 7 is a schematic cross-sectional view along line F-F of the retainer of Figure 2;

Figure 8 is a schematic view of the holder of the invention, seen from the direction of the front end of the feed beam, with separate actuators acting on each clamping arm of the holder;

Figure 9 is a schematic view of the holder of the invention seen from the direction of the front end of the feed beam, the actuator acting on only one clamping arm of the holder;

Figure 10 is a schematic illustration of a second alternative for synchronizing the rotational movement between the clamping arms by a toothed perimeter;

Figure 11 is a schematic view of a third alternative for synchronizing the rotational movement between the clamping arms by means of transverse longitudinal openings arranged in the clamping arms and connecting pins arranged through the openings;

Figure 12 is a further schematic view of a fourth alternative for synchronizing the rotational movement between the clamping arms by means of fixed connecting pins, and longitudinal openings.

Some of the embodiments shown in the figures have been simplified for clarity. Throughout the figures, similar parts are denoted by like reference numerals.

Detailed ways

FIG. 1 shows an excavation apparatus 1 comprising a movable vehicle 2 provided with one or more booms 3 . The first boom 3 a is a drilling boom provided with a rock drilling unit 4 . The drilling unit 4 comprises a rock drilling machine 5 which is movable on a feed beam 6 by means of a feed device 7 . The rock drilling machine 5 may be provided with a tool 8 coupled thereto comprising a plurality of successive drill rods 9 attached to each other by connecting means such as threaded joints. Furthermore, at the distal end of the drill rod there is a drill bit 10 having a drilling button for producing a borehole 12 into the rock 11 . The rock drilling machine 5 may comprise percussion means for delivering percussion pulses to the tool 8 which transmits percussion pulses to the drill bit 10 and further to the rock 11 to be broken up. The rock drilling machine 5 may also comprise rotation means allowing the tool 8 to be rotated about its longitudinal axis during drilling. The drilling unit 4 may also be provided with a drill rod magazine 13 supported on the feed beam 6 . The drill rod magazine 13 can be used to store extension rods 9 and other drilling tools required in long hole drilling. The rod magazine 13 is provided with a switching device for switching the drilling tool between the rod magazine 13 and the drilling axis, ie the center K. The distal end of the feed beam 6 is provided with a holder 14 having claws for clamping and centering the tool 9 in the drilling center K. The jaws can hold the shaft or connecting sleeve of the drill rod 9, thus allowing the rod to be held in place when the joint is tightened or unscrewed. Furthermore, when the drill bit 10 is to be replaced, the drill bit 10 can be grasped and held in place by means of the holder. In addition to the drill rod magazine 13, the feed beam 6 can also be provided with a drill bit magazine.

The second boom 3b of the excavating apparatus 1 of FIG. 1 is provided with a further excavating device 15 for manipulating an excavating tool 16 such as a rock bolt, injection pipe or the like. Also, it may need to be held by the jaws, or the tool may need to be centered to the center K of the device. Also in this case, these excavating devices 15 can be provided with the holder 14 of the invention.

Figure 2 shows a rock drilling unit 4 in which the feed beam 6 is provided with a drill rod magazine 13 in which are the drill rods 9 required for drilling. The distal end of the feed beam 6 is provided with a holder 14, a possible structural alternative of which is shown in more detail in FIGS. 3 to 12 .

The holder 14 of Figure 3 comprises a body 17 allowing it to be attached to the feed beam. The retainer 14 also includes a first clamping arm 18a connected to the body 17 by a first pivot joint 19a and a second clamping arm 18b connected to the body 17 by a second pivot joint 19b. The clamping arm 18 can be moved relative to the pivot joint 19 by the actuator 20 located therebetween, so the clamping jaws 21a, 21b located at the distal end of the clamping arm 18 are naturally dependent on the position of the actuator 20. moving towards each other or away from each other. The actuator 20 may be a pressure medium cylinder, such as a hydraulic cylinder, which may be connected to the clamping arm 18 via a joint 22 . The actuator 20 then transfers the force directly to the clamping arm. The actuator 20 is placed outside the portion between the pivot joints 19a and 19b. The connection point of the actuator 20 , ie the joint 22 is located at a distance from the pivot joints 19 a , 19 b whereby a torque arm is created between the joints 19 and 22 . The clamping jaws 21 may comprise centering surfaces on their surfaces facing each other so that they can precisely center the drill rod 9 or other tool between them into the center K when they are moved towards each other. The centering surface 23 may have a substantially V-shaped cross-section and it is naturally open towards the center K. As shown in FIG. Of course, other inclined or conical centering surfaces 23 can also be used for the clamping jaws 21 . The clamping arms 18 are moved in relation to each other by means of synchronization means 24 arranged on the part between the pivot joints 19 . In other words, the synchronization device 24 is separate from the actuator 20 . FIG. 3 shows a connecting pin 25 which is parallel to the center K and which can belong to the synchronization device 24 . As can be seen, the body 17 is provided with a vertical longitudinal opening 26 which allows movement of the connecting pin 25 in the vertical direction V when the clamping arm 18 is moved.

In FIG. 4 part of the body 17 has been removed for better visibility of the synchronization device 24 . On the part between the pivot joints 19, the first clamping arm 18a may comprise two or more first connecting cams 27 which, when viewing the holder 14 in the direction of the center K, A certain axial distance apart. Correspondingly, the second clamping arm 18b may include two or more second connecting cams 28 . The connecting cams 27 , 28 are staggered on the part between the pivot joints 19 as shown in FIG. 4 . Furthermore, the connecting cams 27 , 28 are provided with connecting slots 29 which may be open towards each other and which are arranged to coincide axially so that together they form a kind of connecting channel 30 . This axial connecting channel 30 is provided with a connecting pin 25 which can be used as a transmission member between connecting cams 27 , 28 . When the clamping arm 18 moves, a movement occurs in the contact surface of the connecting slot 29 and the connecting pin 25, moreover, the connecting pin 25 moves linearly in the vertical direction, ie it moves towards the center K or away from the center K. In this application, the shape surface belonging to the synchronization device 24 is realized by the surface of the connecting channel 30 which is in contact with the connecting pin 25 .

The sectional view of FIG. 5 also clearly shows the formation of the connecting channel 30 between the connecting cams 27 , 28 . For the vertical movement of the connecting pin 25, the body 17 is provided with longitudinal openings 26a, 26b. The cross-sectional views of Figures 6 and 7 further illustrate the construction of this embodiment. Unlike in FIGS. 4 to 7 , a closed shape can be provided for the connection slot 29 . The cross-section of the connection pin 25 is preferably circular.

In the embodiment of Fig. 8, the first actuator 20a only transmits force to the first clamping arm 18a, and the second actuator 20b transmits force only to the second clamping arm 18b. A synchronization device 24 ensures the synchronization of the movement of the clamping arms 18 .

In the embodiment of Fig. 9, only the force from the actuator 20 is transmitted to the first clamping arm 18a, and the synchronization device 24 transmits the motion to the second clamping arm 18b.

FIG. 10 shows a very simplified embodiment of the synchronization device 24 comprising teeth 31 a , 31 b formed in the clamping arm 18 . Teeth are formed in the curved transfer surface of the pivot joint 19 . In this application, the synchronous motion is transmitted directly by contact with the teeth, so no connecting pins or similar connecting members are required. The teeth 31 serve as necessary shape members between the clamping arms 18 .

Figure 11 shows a very simplified embodiment of a synchronization device 24 provided with a first longitudinal connection opening 32a in the first clamping arm 18a and a second longitudinal connection opening 32b in the second clamping arm 18b. The clamping arms 18 are staggered relative to each other, at least on the part connecting the opening 32 . The clamping arm 18 may be provided with connecting cams 27, 28 or corresponding protrusions on these alternating portions. The connecting openings 32 are arranged transversely to one another, so that together they define a connecting channel 30 in which the connecting pin 25 is arranged. The connecting pin 25 is not attached to the connecting opening 32, but is allowed to move longitudinally along the connecting opening 32 when the clamping arm 18 is moved by applying a rotational force to the force transfer point 22, while also moving along the longitudinal direction relative to the center K. Movement in the vertical direction.

FIG. 12 shows yet another very simplified embodiment of a synchronization device 24 with a non-removably fixed clamp formed in the longitudinal connection opening 32 of the first clamping arm 18a and provided on the second clamping arm 18b. The connection pin 25. The clamping arms 18 are staggered relative to each other on the part of the connecting opening 32 and the connecting pin 25 . The clamping arm 18 may be provided with connecting cams 27, 28 or similar protrusions on said staggered portions. When the actuator 20 rotates the clamping arm 18 relative to its pivot 19, the connection pin 25 follows a curved path while its position in the connection opening 32 changes. Furthermore, the connection cam 27 may comprise a slot-shaped connection opening 32 which opens towards the second clamping arm 18b. In this application, the outer surface of the connection pin 25 and the edge of the connection opening 32 serve as shape surfaces for transmitting the synchronous movement.

In the embodiments of Figures 3 to 7, 11 and 12, the connecting pins 25 are arranged between the staggered portions and will substantially only be subjected to shear forces. In this case, the connecting pin 25 can be relatively thin, but it is still capable of transmitting strong forces between the clamping arms 18 . In the embodiment of Figures 3 to 7 and 11 there is a separate connecting pin 25 which is easily removable and replaceable.

It should be noted that the opening movement of the clamping jaws 21 of the holder 14 may be made sufficiently large to allow its use for clamping the connecting sleeve between the shaft of the drill rod 9 and the successive drill rod 9 . Furthermore, the drill bit 10 or any other tool for excavation can be grasped by means of it.

When referring to the vertical direction or vertical movement in this application, this means a vertical movement relative to the basic position of the feed beam and holder, in which position the feed beam is horizontal. This also naturally changes the position of the holder when the boom and feed beam are turned during operation. Although the orientation is changed in an absolute sense, the holder maintains its relative position to the feed beam.

In some cases, features present in this application may be so used independently of other features. However, the features present in this application can also be combined where necessary to provide different combinations.

The drawings and the associated description serve only to illustrate the inventive concept. The details of the invention may vary within the scope of the claims.

Claims (14)

1. method that is used to use the retainer that belongs to excavating equipment, described retainer (14) comprising: body (17); Be pivotally attached to first clamp arm (18a) of described body (17) and clamp jaw (21a, 21b) and at least one actuator (20) of the far-end that second clamp arm (18b) is positioned at described clamp arm (18a, 18b);

Said method comprising the steps of:

By described actuator (20), described clamp arm (18a, 18b) is rotated with respect to the pivoting point (19a, 19b) of described clamp arm (18a, 18b), and described thus clamp jaw (21a, 21b) depends on the direction of motion of described actuator (20) and moves towards one another and leave accordingly motion each other;

By described clamp jaw (21a, 21b), the instrument (9) that will be arranged in the center (K) of described excavating equipment (4,15) is clamped to the center, and is grasping described instrument when described tool positioned is in described center (K);

By the mechanical synchronizer (24) that separates, (18a, 18b) is relative to each other with described clamp arm, and the motion of described clamp arm (18a, 18b) is to be mutually related therefore, and described clamp jaw (21a, 21b) is side by side and motion symmetrically,

It is characterized in that,

Shaped element is arranged on the part between the described pivoting point (19a, 19b) of described clamp arm (18a, 18b), and, make the motion between described first clamp arm (18a) and described second clamp arm (18b) all synchronous along two direct of travels of described clamp arm by described shaped element.

2. according to the method for claim 1, it is characterized in that,

To can compatible tooth (31a, 31b) be arranged into described first clamp arm (18a) and described second clamp arm (18b) and described tooth be arranged relative to one another; And

Touch and between described clamp arm (18a, 18b), transmit and move by direct toe joint.

3. according to the method for claim 1 or 2, it is characterized in that,

Arrange described first clamp arm (18a) and described second clamp arm (18b) at least a portion among both in staggered mode, and the shape face that will provide with the form of opening (29,32a, 32b) is arranged in the above-mentioned alternating share with coincidence; And

By the connecting pin (25) parallel with described center (K), between described clamp arm (18a, 18b), transmit motion, described pin contacts with the described shape face of described clamp arm (18a, 18b).

4. according to the method for claim 3, it is characterized in that,

When described clamp arm (18a, 18b) when moving, allow the transverse movement of described connecting pin (25) vertically.

5. retainer comprises:

Body (17), described body allow described retainer (14) to be attached to the feed beam (6) of excavating equipment (4,15);

First clamp arm (18a) and second clamp arm (18b), described first clamp arm (18a) is connected to described body (17) by first Pivot joint (19a), and described second clamp arm (18b) is connected to described body (17) by second Pivot joint (19b);

Clamp jaw (21a, 21b), described clamp jaw (21a, 21b) are arranged on the part of far-end of described clamp arm (18a, 18b) and face with each other;

At least one actuator (20), described at least one actuator (20) are used to make described clamp arm (18a, 18b) with respect to described Pivot joint (19a, 19b) motion, and described clamp jaw (21a, 21b) can move towards one another and leave motion each other; With

The mechanical synchronizer (24) that separates with described actuator (20), described mechanical synchronizer are used for the motion of described first clamp arm (18a) is correlated with into the motion of described second clamp arm (18b) interrelated,

It is characterized in that,

The described sychronisation (24) of described retainer (14) is arranged on the part between described first Pivot joint and described second Pivot joint (19a, 19b); And

Described sychronisation (24) comprises shaped element, and described shaped element is formed in described first clamp arm and described second clamp arm (18a, 18b) and is arranged to transmit between described clamp arm (18a, 18b) along two direct of travels of described clamp arm and is synchronized with the movement.

6. according to the retainer of claim 5, it is characterized in that,

Described sychronisation (24) comprises the shape face in the structure that directly is formed at described first clamp arm and described second clamp arm (18a, 18b), and described surface is arranged and is arranged through the contact surface that faces with each other on described surface relative to one another and transmit between described clamp arm (18a, 18b) and is synchronized with the movement.

7. according to the retainer of claim 6, it is characterized in that,

Described first clamp arm (18a) and described second clamp arm (18b) are provided with the transmission surface of the bending that faces with each other on the part between the described Pivot joint (19a, 19b); And

Described transmit the surface be provided with can be compatible tooth (31a, 31b), the described contact of being arranged to by tooth that is synchronized with the movement of described clamp arm (18a, 18b) is directly transmitted.

8. according to the retainer of claim 6 or 7, it is characterized in that,

The constant each other contact of described shape face of described clamp arm (18a, 18b).

9. according to the retainer of claim 5, it is characterized in that,

Described sychronisation (24) comprises shape face, is formed on the part of described shape face between described Pivot joint (19a, 19b) in described first clamp arm and described second clamp arm (18a, 18b); And

Described shape face interconnects by the connector (25) that separates, and the described relatively shape face of the connector of described separation ground is arranged, but is not attached to described shape face.

10. according to the retainer of claim 9, it is characterized in that,

Described first clamp arm (18a) comprises that on the part between the described Pivot joint (19a, 19b) at least two first connect cam (27), and described at least two first connect the certain axial distance of cam (27) mutual distance ground and arrange;

Described second clamp arm (18b) comprises that on the part between the described Pivot joint (19a, 19b) at least two second connect cam (28), and described at least two second connect the certain axial distance of cam (28) mutual distance ground and arrange;

The described first connection cam (27) is connected cam (28) with described second staggered;

The described first connection cam (27) is connected cam (28) and is provided with connection slit (29) with described second, described connection slit (29) opens wide toward each other, and described connection slit (29) is arranged to overlap as follows, that is: make the connection slit (29) that is positioned on the opposite side be arranged to form vertically interface channel (30);

Connecting pin (25) is arranged in the described interface channel (30), and is arranged to connect the cam and described second transmission member that connects between the cam (27,28) as described first; And

When described clamp arm (18a, 18b) moves, described connecting pin (25) freely-movable vertically.

11. the retainer according to claim 5 is characterized in that,

Described first clamp arm (18a) comprises the connecting pin (25) that is parallel to described center (K) on the part between the described Pivot joint (19a, 19b), described pin is being fixed to described first clamp arm (18a) by move mode;

Described second clamp arm (18b) comprises vertical connection opening (32) on the part between the described Pivot joint (19a, 19b); And

Described connecting pin (25) is arranged to pass described connection opening (32), and described thus connecting pin (25) and described connection opening (32) are transmitted as shaped element and between described clamp arm (18a, 18b) and be synchronized with the movement.

12. any one the retainer according in the aforementioned claim 5 to 11 is characterized in that,

Described retainer (14) comprises an only actuator (20), and described actuator is disposed between the described clamp arm (18a, 18b) and is connected to and acts directly on two clamp arms (18a, 18b).

13. any one the retainer according in the aforementioned claim 5 to 11 is characterized in that,

Described retainer (14) comprises an only actuator (20), and described actuator is arranged to only act on described first clamp arm (18a), and described second clamp arm (18b) is arranged to move under the influence of described sychronisation simultaneously.

14. any one the retainer according in the aforementioned claim 5 to 11 is characterized in that,

Described retainer (14) comprises at least two actuators (20a, 20b), at least one first actuator (20a) is connected to and only acts directly on described first clamp arm (18a), and at least one second actuator (20b) is arranged to only act directly on described second clamp arm (18b).

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