WO2009048412A1

WO2009048412A1 - A milking member and method of preparing it for attachment

Info

Publication number: WO2009048412A1
Application number: PCT/SE2008/051124
Authority: WO
Inventors: Torbjörn Petterson; Ola Sandberg
Original assignee: Delaval Holding Ab
Priority date: 2007-10-09
Filing date: 2008-10-03
Publication date: 2009-04-16
Also published as: DE112008002702T5

Abstract

The invention refers to a milking device for milking an animal during a milking operation, and to a method of milking. The milking device comprises a milking member (5) with set of teatcups (6) adapted to be attached to the teats of the animal, a support device (15) and a removing device (30) comprising a drive member (31) and a line element (33) connecting the milking member to the drive member. The removing device removes automatically the milking member from the animal and moves the milking member to a rest position during a removing operation after the milking operation. The drive member exerts a pulling force on the line element and collects a line portion of the line element during the removing operation. Furthermore, the removing device feeds out at least a part of the line portion during a preparation operation after the removing operation.

Description

A milking member and method of preparing it for attachment

TECHNICAL FIELD OF THE INVENTION AND PRIOR ART

The present invention refers to a milking device according to the preamble of claim 1. Furthermore, the present invention refers to a method of milking according to the preamble of claim 15.

There are several different milking methods known today. One differs between manual milking, where the milking operation is performed by hand, and machine milking, where the milking is performed by a milking machine. Machine milking may be semi-automatic, i.e. the teatcups are attached manually but automatically removed from the teats after the milking operation is finished. Such semi-automatic milking is the most frequent method today, especially in milking arrangements comprising a large number of animals. This invention refers to an arrangement to be operated according to the semi-automatic milking method. In such an arrangement, the attachment of the teatcups is still a rather heavy and time-consuming work. The operator has to move the teatcups to a position beneath the teats and to lift the teatcups for the attachment of the teatcups to the teats.

WO 93/00002 discloses a milking device for semi-automatic milking of an animal during a milking operation. The device comprises a milking member comprising a set of teatcups adapted to be attached to the teats of the animal to be milked during the milking operation, and a removing device comprising a drive member and a line element connecting the milking member to the drive member and being in an extended state during the milking operation. The removing device is adapted to remove automatically the milking member from the animal and to move the milking member to a rest position during a removing operation when the milking operation is finished. During the removing operation the drive member thus exerts a pulling force on the line element and collects a part of the line element on a rotating drum. WO2006/073369 discloses a milking device for milking an animal during a milking operation. The known milking device comprises a milking member comprising at least one teatcup adapted to be attached to a teat of the animal to be milked during the milking operation, a support device and a removing device comprising a drive member and a line element connecting the milking member to the drive member and being in an extended state during the milking operation. The removing device is adapted to remove the milking member from the animal and to move the milking member to a rest position when the milking operation is finished during a removing operation. During the removing operation the drive member exerts a pulling force on the line element and collects at least a part of the line element.

These known milking devices for semi-automatic milking are thus designed to permit automatic removal of the milking member when the milking operation has been finished. The milking member is retracted and moved to a rest position behind or beside the animal. In this rest position, the milking member will not obstruct the animal, but the milking member remains locked in the rest position until the next milking operation. When a new milking operation is to be initiated, the milker has to deactivate the removing device, which maintains the milking member in the rest position, in order to move the milking member from the rest position to a position straight beneath the teats of the animal to be milked, and to attach the milking member to the teats of the animal. The deactivation of the removing device, for instance by pushing a button, means that the energy (e.g. electric or pneumatic) supply to the removing device is interrupted and that the line element can be extended. However, a significant pulling force is still required for pulling out the line element so that the milking member can be moved from the rest position. This pulling operation is tiring and time-consuming.

WO 2006/073370 discloses another milking device for semi-automatic milking of an animal during a milking operation. The milking device comprises a milking member with a set of teatcups to be attached to the teats of the animal to be milked during the milking operation, a support device and a retraction device comprising a drive member. The retraction device removes the milking member from the animal and moves the milking member to an idle position or rest position when the milking operation is finished. The support device, is in this instance designed to move automatically the milking member from the idle position to an intermediate position, in which the milking member is still attached to the support device but at a position beneath the teats of the animal.

SUMMARY OF THE INVENTION

The object of the present invention is to remedy the problems discussed above and to provide a milking device which permit an easy manual attachment of the milking member to the teats.

This object is achieved by the milking device initially defined, which is characterised in that the removing device is adapted to feed out at least a part of the line portion during a preparation operation after the removing operation.

By means of such a removing device, the line portion of the element will thus be fed out from the removing device before the milker grips the milking member for attaching the milking member to the teat of the animal. Consequently, the milker does not need to pull out the line element before the actual attachment of the milking member to the teat. The attachment procedure is thus facilitated, and can be performed in a quick and easy manner.

According to an embodiment of the invention, the milking device comprises a support device which is adapted to maintain the milking member in the rest position during the preparation operation. Consequently, although the line element after being fed out will hang down from the removing device, the milking member is still maintained in the rest position prepared for being moved to beneath the teats of the animal and then attached to the teat. The milking member is thus prevented from falling down onto the ground and from being contaminated.

According to a further embodiment of the invention, the preparation operation is an automatic preparation operation during which the removing device is adapted to feed out automatically the part of the line portion. Consequently, the milker does not need to take any action for feeding out the line element, but the line portion of the line element will be fed out automatically so that the milking member is prepared for attachment already when the milker arrives at the animal to be milked.

According to a further embodiment of the invention, the removing device is adapted to feed out the part of the line portion during the preparation operation until the line element has reached the extended state. In such a manner, it is ensured that the milking member reaches the teat, without the need of any further pulling action of the milker during the attachment procedure.

According to a further embodiment of the invention, the removing device comprises a collecting member for collecting the line portion.

Advantageously, the drive member may comprise a rotary motor and the collecting member a drum, which is connected to the rotary motor. The drum may then be rotatable by means of the rotary motor in a first direction during the removing operation in order to wind up the line portion of the line element onto the drum, and in a second opposite direction during the preparation operation in order to feed out the line element.

According to a further embodiment of the invention, the drive member comprises a linear motor. Such a linear motor may have a linearly movable piston or the like, which may be directly connected to the line element.

According to a further embodiment of the invention, the milking device comprises a control unit adapted to control the removing device. Advantageously, the milking device may then comprise a first sensor connected to the control unit and adapted to sense when the milking member is in the rest position, wherein the control unit is adapted to interrupt the removing operation and then to initiate the preparation operation when the first sensor senses that the milking member has reached the rest position. Furthermore, the milking device may, as an alternative or supplement, comprise a second sensor connected to the control unit and adapted to sense a value of a parameter related to the pulling force exerted on the line element, wherein the control unit is adapted to interrupt the removing operation and then to initiate the preparation operation when the second sensor senses that the value of the parameter exceeds a determined level.

According to a further embodiment of the invention, the support device comprises a support arm to which the milking member is connected during the removing operation and the preparation operation. By means of such a support arm, the milking member may be securely maintained in the rest position, although the line element has been fed out. Advantageously, the support arm may extend along an arm axis and be extendable along the arm axis. Furthermore, the support device may comprise a mounting device, adapted to be mounted to a structure, wherein the support arm is mounted to the mounting device by means of a rotary joint permitting rotation of the support arm.

The object is also achieved by the method initially defined, which is characterised by the further step of feeding out at least a part of the line portion during a preparation operation after the removing operation.

Preferred further method steps are defined in the dependent claims 16 to 18.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is now to be explained more closely by means of a description of various embodiments and with reference to the drawings attached hereto.

Fig 1 discloses schematically a side view of a first embodiment of a milking device according to the invention in an active milking position. Fig 2 discloses a view from above of the milking device in Fig 1 in an intermediate position. Fig 3 discloses schematically a side view of the milking device in Fig 1 in a rest position immediately after a removing operation. Fig 4 discloses schematically a side view of the milking device in the rest position immediately after a preparation operation. Fig 5 discloses schematically a side view of a drive member of a removing device of the milking device in Fig 1. Fig 6 discloses schematically a side view of a second embodiment of a milking device according to the invention in an active milking position.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS OF THE INVENTION

Figs 1 to 4 disclose a first embodiment of a milking device 1 for milking an animal during a milking operation. The milking device 1 is provided in a stationary structure 2 in the form of a milking stall. The milking stall comprises at least one or a large number of milking places 3 arranged in any preferred configuration for receiving a respective animal to be milked. Each milking place 3 is adapted to house one animal for being milked during a milking operation.

The milking device 1 comprises a milking member 5 comprising at least one teatcup 6 to be attached to a teat of the animal to be milked. In the embodiments disclosed, the milking member 5 comprises a claw 7 and four teatcups 6. Each teatcup 6 is connected to the claw 7 via a respective short milk conduit 8. Each teatcup 6 defines an inner space for receiving a respective teat and has an upper opening 9 permitting the introduction of the teat into the inner space of the teatcup 6. Each short milk conduit 8 has such a stiffness that the teatcups 6 are maintained in a position with the openings 9 turned substantially upwards also when the teatcups 6 are not attached to the teats of the animal and the claw is in a substantially horizontal position as shown in Fig 1.

As can be seen in Fig 1 , each short milk conduit 8 is attached to the respective teatcup 6 at an upper part of an outer side surface of the teatcup 6. Each short milk conduit 8 has a first substantially straight portion connected to the claw 7 and a second substantially straight portion connected to the respective teatcup 6. The first straight portion is approximately perpendicular to the second straight portion. In the position disclosed in Fig 1 , the first straight portion extends substantially vertically and the second straight portion extends substantially horizontally.

A long milk conduit 10 extends from the milking member 5. In the embodiment disclosed in Figs 1-4, the long milk conduit 10 is attached to and extends from the claw 7. The long milk conduit 10 is adapted to be connected to a milking machine (not disclosed) in a manner known per se. It should also be noted that each teatcup 6 in a conventional manner comprises a pulsation chamber (not disclosed) connected to a pulsator (not disclosed) via pulse conduit (not disclosed), which could be a separate conduit or a conduit integrated in the short milk conduit 8 and/or the long milk conduit 10.

The milking device 1 also comprises a support device 15. The support device 15 comprises a mounting device 16 and a support arm 17a, 17b.

The support arm 17a, 17b has an elongated shape and extends in parallel to an arm axis x. The mounting device 16 is adapted to be movably, or fixedly, mounted to the stationary structure 2. In the embodiments disclosed, the stationary structure 2 comprises a rail element 18 provided outside the milking place 3 and mounted to a substantially vertical wall 13 next to and beneath the milking place 3. The rail element 18 extends in parallel to or along a horizontal or substantially horizontal rail axis r. It should be noted that the rail axis r could be inclined with respect to a horizontal line. The mounting device 16 is mounted to the rail element 18 to be freely movable on the rail element 18 along the rail axis r at least during the milking operation.

The support arm 17a, 17b is connected to the mounting device 16 via a connecting member 19. The support arm 17a, 17b is movable with respect to the mounting device 16. In the embodiments disclosed, the support arm 17a, 17b is rotatable in a vertical plane with respect to the mounting device 16. This possibility of rotation of the support arm 17a, 17b is accomplished by means of a rotary joint 19' of the connecting member 19. The connecting member 19 is thus mounted to the mounting device 16 by means of the rotary joint 19'. The milking member 5 is connected to or attached to the support arm 17a, 17b and is at the same time freely movable along the arm axis x. This movability is accomplished in two ways. The milking member 5 is displaceable on the support arm 17a, 17b along the arm axis x. The milking device 1 may then comprise a slide member 20, which holds the milking member 5 and is slideably attached to the support arm 17a, 17b to be displaceable along the arm axis x. More specifically, as can be seen from the figures, the slide member 20 holds the claw 7 via two pins 21 attached to the claw 7 and extending through corresponding holes extending through two flange members 22 provided on the slide member 20. The claw 7 is pivotal with respect to the slide member 22 by means of the pins 21. More specifically, the claw 7 is pivotal around a pivot axis p extending in parallel to the pins 21. In the embodiments disclosed, the pivot axis p extends at a substantially right angle in relation to the arm axis x. The flange members 22 are elastically flexible so that the claw 7 and the milking member 5 can be easily detached from the slide member 20 by bending the flange members 22 outwardly.

The support arm 17a, 17b comprises a primary arm element 17a', 17b' connected to the mounting device 16 and a secondary arm element 17a", 17b" holding the milking member 5. The movability of the milking member 5 is also accomplished by the support arm 17a, 17b being extendable. In the embodiments disclosed the primary arm element 17a', 17b' is telescopically introduceable into the secondary arm element 17a", 17b" so that the secondary arm element 17a", 17b" is displaceable and freely movable on the primary arm element 17a', 17b' along the arm axis x. The support arm 17a, 17b has an inner end connected to the mounting device 16 and an opposite outer end. The milking member 5 is thus displaceable on the support arm 17a, 17b between a first inner position in the proximity of the inner end, see Fig 3, and a second outer position in the proximity of the outer end, see Fig 1. Furthermore, the support arm 17a, 17b is, as mentioned above, connected to the mounting device 16 to be movable with respect to the mounting device 16 in order to be positionable in at least a rest position shown in Figs 3 and 4, and an active milking position shown in Fig 1. As can be seen from Fig 2, the support arm 17a, 17b may comprise a first arm 17a and a second arm 17b. The teatcups 6 and the short milk conduits 8 are not disclosed in Fig 2. Both the first arm 17a and the second arm 17b extend in parallel to each other and to the arm axis x. Both the first arm 17a and the second arm 17b are at the inner ends connected to the mounting device 16 via the connecting element 19. At the outer ends the first arm 17a and the second arm 17b are connected to each other via a connecting rod 25. The long milk conduit 10 extends beside the support arm 17a, 17b and in the first embodiment, the long milk conduit 10 extends between the first arm 17a and the second arm 17b. The slide member 20 is mounted to the first arm 17a and the second arm 17b to be displaceable along the arm axis x. Both the first arm 17a and the second arm 17b comprise a respective primary arm element 17a', 17b' connected to the mounting device 19 and a respective secondary arm element 17a", 17b" holding the milking member 5. The primary arm elements 17a', 17b' are telescopically introduceable into the secondary arm elements 17a", 17b" in such a way that the secondary arm elements 17a", 17b" are displaceable on the respective primary arm element 17a', 17b' in parallel to the arm axis x.

The milking device 1 also comprises a removing device 30 provided to remove automatically the milking member 5 from the teats of the animal during a removing operation after the milking operation has been finished, and to move the milking member 5 to, or towards, the rest position shown in Figs 3 and 4. The removing device 30 comprises a drive member 31 attached to the stationary structure 2, and in the embodiments disclosed to the wall 13. It is to be noted that the drive member 31 could also be attached to for instance the mounting device 16. In the first embodiment, the drive member 31 comprises a rotary motor 39, for instance an electric motor, a pneumatic motor or a hydraulic motor, see Fig 5.

Furthermore, the removing device 30 comprises a guide member 32, which is attached to the connecting member 19 and fixed in relation to the support arm 17a, 17b. The removing device also comprises a line element 33, such as a cord, a wire, a chain etc. The line element 33 extends between and is connected to the drive member 31 and the milking member 5. The extension of line element 33 is at least during the milking operation and an initial phase of the removing operation partly determined by the guide member 32. During the milking operation, the line element 33 is in an extended state. During the removing operation, the drive member 31 is thus adapted to exert a pulling force on the line element 33 and to collect a line portion of the line element 33. To that end, referring to Fig 5, the removing device 30 comprises a collecting member 40, which comprises a drum 41 , a pulley, a reel or the like. The drum 41 is connected to the rotary motor 39 of the drive member 31 , and more specifically to a rotary shaft of the rotary motor 39, to be rotatable. The drum 41 is rotatable by means of the rotary motor 39 in a first direction during the removing operation in order to wind up the line portion of the line element 33 onto the drum 41 , and thus to collect the line portion on the drum 41.

Furthermore, the removing device 30 is adapted to feed out at least a part, or the whole, of the collected line portion of the line element 33 during a preparation operation after the removing operation at least when the milking member has reached the rest position. The preparation operation thus follows the removing operation, for instance immediately after the removing operation and at least before the subsequent milking operation is to take place. The preparation operation may be an automatic preparation operation during which the removing device 30 is adapted to feed out automatically the part of the collected line portion. Moreover, the removing device 30 may be adapted to feed out the collected part of the line portion until the line element 33 has reached the extended state, see Fig 4. During the preparation operation, the drum 41 is rotated in a second opposite direction by means of the rotary motor 39 in order to feed out the line element 33 from the drum 41 and the collecting member 40. As can be seen in Figs 3 and 4, the support device 15 is adapted to maintain the milking member 7 in the rest position during the preparation operation.

In order to be able to perform the removing operation and the preparation operation in an automatic manner, the milking device may also comprise a control unit 34, adapted to control the removing device 30 and the drive member 31 , a first sensor 35 and/or a second sensor 36. The automatic initiation of the removing operation is known and therefore not described in this application.

The first sensor 35 is connected to the control unit 34 and adapted to sense when the milking member 7 is in the rest position. The first sensor 35 may be realised by a proximity sensor of a known kind. The control unit 34 is adapted to interrupt the removing operation and to initiate the preparation operation in an automatic manner when the first sensor 35 senses that the milking member 5 has reached the rest position.

The second sensor 36 is connected to the control unit 34 and adapted to sense a value of a parameter related to the pulling force exerted on the line element 33. The second sensor 36 may be realised by a sensor sensing the torque of the drive member 31 or in case of an electric drive member, the electric power supplied to the drive member 31. In the latter case, the second sensor 36 may be incorporated in the control unit 34 proper. The control unit 34 may thus also be adapted to interrupt the removing operation and to initiate the preparation operation in an automatic manner when the second sensor 36 senses that the value of the parameter exceeds a determined level. Thanks to the second sensor 35, it is thus possible to interrupt the removing operation and initiate the preparation operation even if the milking member 5 has not yet reached the rest position. If for any reason it may not be possible to pull the milking member 5 to the rest position, the milking member 5 being stuck at an intermediate position.

As indicated above, Fig 1 discloses the milking device 1 in an active milking position in which the milking member 5 is located at an outer end of the support arm 17a, 17b and the teatcups 6 may be attached to the teats of the animal (not disclosed). Figs 3 and 4 disclose the milking device 1 in a rest position, in which the milking member 5 is located at the inner end of the support arm 17a, 17b. In the rest position, the support arm 17a, 17b has been rotated in a vertical plane with respect to the mounting device 16 so that the support arm 17a, 17b is located completely outside the milking place 3, or at least substantially completely outside the milking place 3. In the rest position shown in Fig 4, i.e. after the preparation operation, the milking member 5 and the teatcups 6 may be easily attached to the teats of an animal by a milker. The milker may then grip two of the teatcups 6 and move them forwardly, i.e. from the position outside the milking parlour 3 to a position beneath the udder and the teats of the animal, without any resistance from the drive member 31 and the line element 33. In the embodiments disclosed, this movement is permitted by the rotation of the support arm 17a, 17b around the connecting joint 19' and by the movement of the milking member 5 along the arm axis x. From the position beneath the teats, the teatcups 6 can be slightly lifted onto the respective teats. The animal may then be milked during the milking operation. When the milking operation is finished, the removing device 30 is activated, wherein the milking member 5 is withdrawn from the teats and moved to or towards the rest position.

It is to be noted that the support arm 17a, 17b may be arranged to extend between the rear legs of the animal to be milked or to extend between a rear leg and a front leg of the animal.

Fig 6 discloses a second embodiment of the milking device. It is to be noted that elements having a corresponding function have been denoted with the same reference signs in all embodiments. The second embodiment differs from the first embodiment in that the drive member 31 , instead of a rotary motor 39, comprises a linear motor, for instance an electric linear motor or a pneumatic or hydraulic linear motor, such as a pneumatic or hydraulic cylinder. Such a linear motor may have a linearly movable piston or the like, which may be directly connected to the line element 33, wherein the collecting member may be formed by a housing in which the piston is contained. The linear motor may also be adapted to drive a collecting member of any suitable kind, such as a drum.

The present invention is not limited to the embodiments disclosed but may be varied and modified within the scope of the following claims. The support arm 17a, 17b may instead of having two parallel arms 17a, 17b as shown in Fig 2 be provided with only one arm. In the embodiments disclosed, the milking member 5 comprises a claw 7. It should be noted that the milking member 5 also may comprise the teatcups 6 and a respective long milk conduit 10 for each teatcup 6, wherein the long milk conduits 10 are directly connected to the respective teatcup 6 permitting so called quarter milking.

It is also to be noted that the support device 15 may be designed in various ways and not only in the manner described above. It is important that the support device 15 is able of maintaining the milking member 5 in the rest position during the preparation operation when the line element 33 has been fed out. However, the milking member 5 does not have to be attached to the support device 15 or the support arm 17a, 17b when the milker is to attach the teatcups 6 to the teats of the animal. Consequently, the present invention may also be realised with a support device which does not include a support arm extending to a position beneath the teats of the animal.

Claims

1. A milking device for milking an animal during a milking operation, comprising a milking member (5) comprising at least one teatcup (6) adapted to be attached to a teat of the animal to be milked during the milking operation, and a removing device (30) comprising a drive member (31 ) and a line element (33) connecting the milking member (5) to the drive member (31 ) and being in an extended state during the milking operation, wherein the removing device (30) is adapted to remove automatically the milking member (5) from the animal and to move the milking member (5) towards a rest position during a removing operation when the milking operation is finished, wherein the drive member (31 ) is adapted to exert a pulling force on the line element (33) and to collect a line portion of the line element (33) during the removing operation, characterised in that the removing device (30) is adapted to feed out at least a part of the line portion during a preparation operation after the removing operation.

2. A milking device according to claim 1 , wherein the milking device comprises a support device (15) which is adapted to maintain the milking member (5) in the rest position.

3. A milking device according to any one of claims 1 and 2, wherein the preparation operation is an automatic preparation operation during which the removing device (30) is adapted to feed out automatically the part of the line portion.

4. A milking device according to any one of the preceding claims, wherein the removing device (30) is adapted to feed out the part of the line portion during the preparation operation until the line element (33) has reached the extended state.

5. A milking device according to any one of the preceding claims, wherein the removing device (30) comprises a collecting member (40) for collecting the line portion.

6. A milking device according to claim 5, wherein the drive member (31 ) comprises a rotary motor (39) and the collecting member (40) comprises a drum (41 ), which is connected to the rotary motor (39).

7. A milking device according to claim 6, wherein the drum (41 ) is rotatable by means of the rotary motor (39) in a first direction during the removing operation in order to wind up the line portion onto the drum (41 ), and in a second opposite direction during the preparation operation in order to feed out the line element (33).

8. A milking device according to any one of claims 1 to 5, wherein the drive member (31 ) comprises a linear motor.

9. A milking device according to any one of the preceding claims, wherein the milking device comprises a control unit (34) adapted to control the removing device (30).

10. A milking device according to claim 9, wherein the milking device comprises a first sensor (35) connected to the control unit (34) and adapted to sense when the milking member (5) is in the rest position, wherein the control unit (34) is adapted to interrupt the removing operation and then to initiate the preparation operation when the first sensor (35) senses that the milking member (5) has reached the rest position.

11. A milking device according to any one of claims 9 and 10, wherein the milking device comprises a second sensor (36) connected to the control unit (34) and adapted to sense a value of a parameter related to the pulling force exerted on the line element (33), wherein the control unit (34) is adapted to interrupt the removing operation and then to initiate the preparation operation when the second sensor (36) senses that the value of the parameter exceeds a determined level.

12. A milking device according to at least claim 2, wherein the support device (15) comprises a support arm (17a, 17b) to which the milking member (5) is connected during the removing operation and the preparation operation.

13. A milking device according to claim 12, wherein the support arm (17a, 17b) extends along an arm axis (x) and is extendable along the arm axis (x).

14. A milking device according to any one of claims 12 and 13, wherein the support device (15) comprises a mounting device (16), adapted to be mounted to a structure (2), wherein the support arm (17a, 17b) is mounted to the mounting device (16) by means of a rotary joint (19) permitting rotation of the support arm (17a, 17b).

15. A method of milking an animal with a milking member having at least one teatcup, comprising the steps of: attaching the teatcup to a teat of the animal to be milked, milking the animal during a milking operation, and automatically removing the milking member from the animal and moving the milking member towards a rest position during a removing operation when the milking operation is finished by exerting a pulling force on a line element connected to the milking member so that a line portion is collected, characterised in that the method comprises the further step of: feeding out at least a part of the line portion during a preparation operation after the removing operation.

16. A method according to claim 15, comprising the further step of maintaining the milking member in the rest position during the preparation operation.

17. A method according to any one of claims 15 and 16, wherein the feeding out of the part of the line portion is performed automatically during the preparation operation.

18. A method according to claim 17, wherein the part of the line portion is fed out during the preparation operation until the line element has reached an extended state.