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Title:
A MILKING UNIT, A MILKING APPARATUS AND A METHOD FOR CONTROLLING SUCH AN APPARATUS
Document Type and Number:
WIPO Patent Application WO/1998/011773
Kind Code:
A1
Abstract:
A milking unit (1) comprises a teatcup (2) in which there is formed a chamber (7) for receiving a teat. According to the invention, a viewing means (8) is arranged to view the chamber (7). Furthermore, a milking apparatus comprises at least one such milking unit (1). Additionally, a method of controlling a milking apparatus having such a milking unit is described.

Inventors:
OERNERFORS BENNY (SE)
Application Number:
PCT/SE1997/001543
Publication Date:
March 26, 1998
Filing Date:
September 12, 1997
Export Citation:
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Assignee:
ALFA LAVAL AGRI AB (SE)
OERNERFORS BENNY (SE)
International Classes:
A01J5/003; A01J5/007; A01J5/017; A01J5/08; (IPC1-7): A01J5/007
Foreign References:
DE3742742A11989-07-06
US1430191A1922-09-26
GB2272971A1994-06-01
EP0527509A21993-02-17
EP0645079A11995-03-29
SE438076B1985-04-01
US4726322A1988-02-23
US4222346A1980-09-16
Attorney, Agent or Firm:
Berglund, Stefan (�stermalmsgatan 58, Stockholm, SE)
Download PDF:
Claims:
Claims
1. A milking unit (1) comprising a teatcup (2) in which there is formed a chamber (7) for receiving a teat, characterised by a viewing means (8) arranged to view the chamber (7) .
2. A milking unit according to claim 1, wherein the viewing means (8) is provided in said chamber (7) .
3. A milking unit according to claim 1 or 2, in which said teatcup (2) comprises a liner (4) delimiting said chamber (7), wherein said viewing means (8) is provided on said liner (8) .
4. A milking unit according to claim 1, in which said teatcup (2) comprises a liner (4) delimiting said chamber (7), wherein said liner (4) is transparent at least in part and said viewing means (8) is provided outside said liner (4) .
5. A milking unit according to claim 4, in which said teatcup (2) comprises a shell (3) , said shell and liner delimiting a space (5), wherein said viewing means (8) is arranged in said space (5) .
6. A milking unit according to claim 1, in which said teatcup (2) comprises a shell (3) surrounding said chamber (7), wherein said shell (3) is transparent at least m part and the viewing means (8) s arranged outside said shell (3) .
7. A milking unit according to claim 6, in which a liner (4) delimiting said chamber (7) is provided in said shell (3), said liner (4) being transparent at least in part.
8. A milking unit according to claim 6 or 7, further comprising a support (13) for said teatcup (2), said viewing means (8) being supported by said support (13) .
9. A milking unit according to anyone of the preceding claims, in which an illuminating means (11a) is provided for illumination of at least a part of said chamber (7) .
10. A milking apparatus comprising a control means (15) for controlling operation of the milking apparatus, characterised in that it further comprises at least one milking unit (1) according to anyone of the preceding claims, said viewing 20 means (8) being operably connected to said control means (15) .
11. A milking apparatus according to claim 10, wherein said milking unit (1) is adapted to be moved together with a robot arm (13) in relation to an animal, said robot arm (13) being operable by said control means in response to said viewing means for enabling proper attachment of said teatcup (2) to a teat of said animal.
12. A milking apparatus according to claim 11, wherein said control means (15) is adapted to commence and interrupt a milking operation regarding said teatcup, in response to said viewing means.
13. A milking apparatus according to claim 11 or 12, wherein a teatcup cleaning means (23) is operable by said control means (15) for cleaning of said teatcup (2) in response to said viewing means (8) .
14. A milking apparatus according to anyone of claims 11 to 13, wherein said teatcup (2) is connectible to a milk line (21) and wherein a milk line cleaning means (23) is operably connected to said control means (15) for cleaning of at least a part of said milk line (21) .
15. A milking apparatus according to anyone of claims 11 to 14, wherein a signal transmitter (25) for transmitting a signal to an attention bringing means is operable by said control means in response to said viewing means.
16. A method of controlling a milking apparatus, comprising a control means (15) and a milking unit (1) having a teatcup (2) in which there is formed a chamber (7) for receiving a teat, characterised by viewing said chamber (7) of the teatcup (2) by means of a viewing means (8), establishing in response to said viewing means the existence of a milking related condition by means of said control means (15), and controlling said milking apparatus by said control means to perform an appropriate action in response to said established milking related condition.
17. A method according to claim 16, including establishing, as said milking related condition, the existence of a correctly positioned teat in the chamber (7) of said teatcup (2), and starting a milking operation by means ' of said control means (15) .
18. A method according to claim 16 or 17, including establishing, as said milking related condition, the existence of a milk flow in the chamber (7) of said teatcup.
19. A method according to claim 16, including establishing, as said milking related condition, a folded teat, detaching the teatcup (2) from the teat as a consequence thereof and reattaching it thereafter to the teat by means of a robot arm (13) .
20. A method according to claim 16, including controlling said milking apparatus to interrupt a milking operation at least regarding said teatcup (2) , in response to said established milking related condition, and to remove said teatcup from the teat.
21. A method according to claim 20, including establishing, as said milking related condition, a ceasing milk flow from said teat into the chamber (7) of said teatcup (2), and interrupting said milking operation, as a consequence thereof.
22. A method according to claim 20, including establishing, as said milking related condition, a dirty teat, detaching the teatcup from the teat as a consequence thereof, thereafter cleaning the teat by means of a teat cleaning means, and subsequently reattaching the teatcup onto said teat by means of a robot arm.
23. A method according to claim 20, including establishing, as said milking related condition, that at least a part of a surface delimiting said chamber is dirty.
24. A method according to claim 20, including establishing, as said milking related condition, an undesired substance in the milk extracted from said teat, detaching the teatcup (2) from the teat as a consequence thereof, returning the extracted milk through the teatcup (2) in a direction, which is opposite to the flow direction of milk during milking, and to be let out through an opening (7a) , which is adapted to receive a teat during milking.
25. A method according to anyone of claims 21 to 24, wherein said teatcup (2) is cleaned by switching a valve (19) from a milking mode (MM) to a teatcup cleaning mode (TCM) , thereby allowing a cleaning liquid to flow from a cleaning means (23) to said teatcup (2) in a direction, which is opposite to the flow direction of milk during milking, and to be let out through an opening (7a) , which is adapted to receive a teat during milking.
26. A method according to claim 25, including establishing, as said milking related condition, the existence of a cleaning liquid in the chamber (7) of said teatcup (2) .
27. A method according to claim 26, including establishing, as said milking related condition, a predetermined level of cleanliness of said cleaning liquid and interrupting the flow in response thereto.
28. A method according to claim 20, including establishing, as said milking related condition, malfunction of said teatcup liner (4), and detaching as a consequence thereof the teatcup (2) from said teat.
29. A method according to claim 20, including establishing, as said milking related condition, a bad condition of said teat, and removing as a consequence thereof the teatcup (2) from said teat.
30. A method according to claim 22 or 29, including establishing, as said milking related condition, data regarding the shape and/or colour of an animal individual's teats, respectively, storing said data, and using said data as reference while establishing the condition of said teat.
31. A method according to claims 28 or 29, including transmitting a further signal from said control means (15) by means of a signal transmitting means (25) to an attention bringing means (26) , as a consequence of said establishment of a milking related condition.
Description:
A milking unit, a milking apparatus and a method for controlling such an apparatus

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a milking unit comprising a teatcup in which there is formed a chamber for receiving a teat.

The invention also relates to a milking apparatus having a control means for controlling operation thereof and comprising such a milking unit and a method of controlling such a milking apparatus.

BACKGROUND OF THE INVENTION

A milking unit and a milking apparatus of this kind, respectively, is disclosed in WO 94/23565, in which a teatcup attached to a teat is used as reference during attachment of the rest of the teatcups. This is performed by radiating an ultrasonic beam towards a reflecting element arranged on a referential teatcup attached to a teat. No other information regarding the relevant teat or teatcup is possible to derive.

In EP-A-0 300 115, another milking unit and a milking apparatus, respectively, is disclosed, in which the position of the teats of a cow is established by approaching a camera towards the teats from below. A control apparatus connects a robot arm to the camera, the information of which is used to perform attachment of a teatcup onto each teat. Only the position of the relevant teat or teatcup is possible to derive from said information.

In EP-A-0 468 588 the absence of a milk flow is established by means of i.a. a temperature sensor.

In EP-A-0 209 205, a sensor inside a liner of a teatcup is provided to establish the presence of a teat therein.

SUMMARY OF THE INVENTION

The object of the invention is to provide an efficient monitoring of said milking unit.

This object is obtained by a milking unit and a milking apparatus, ' respectively, as initially defined, which is characterised by a viewing means arranged to view the chamber.

The object is also obtained by a method as initially defined, which is characterised by viewing said chamber of the teatcup by means of a viewing means, establishing in response to said viewing means the existence of a milking related condition by means of said control means, and controlling said milking apparatus by said control means to perform an appropriate action in response to said established milking related condition.

By said milking unit, milking apparatus and method of controlling a milking apparatus, respectively, is achieved a safe establishment of the condition of the interior of the teatcup or the condition of a teat inserted thereinto. Consequently, the milking of an animal is allowed to be performed automatically.

According to a first embodiment of the invention, the viewing means is provided in said chamber. Preferably, said teatcup comprises a liner delimiting said chamber, wherein said viewing means is provided on said liner. Hereby is achieved that the viewing means may view the chamber unobstructedly by any wall means.

According to a second embodiment of the invention, said teatcup comprises a liner delimiting said chamber, wherein said liner is transparent at least in part and said viewing means is provided outside said liner. Hereby is achieved a possibility of arranging a viewing means sheltered from milk passing through the chamber.

Preferably, said teatcup comprises a liner and a shell, said shell and liner delimiting a space, wherein said viewing means is arranged in said space. Hereby is achieved a possibility of arranging a viewing means sheltered from exterior dirt, e.g. manure, and from external stress because of the animal's movements, such as kicks.

According to a third embodiment, said teatcup comprises a shell surrounding said chamber, wherein said shell is transparent at least in part and the viewing means is arranged outside said shell. Hereby is achieved a possibility of viewing the chamber from a distance.

Preferably, a liner delimiting said chamber is provided in said shell, said liner being transparent at least in part.

Even more preferably said milking unit further comprises a support for said teatcup, said viewing means being supported by said support. Hereby is achieved a static relation between the teatcup and the viewing means.

Advantageously, an illuminating means is provided for illumination of at least a part of said chamber. Hereby is achieved a possibility of using the viewing means during bad light conditions.

Preferably, said viewing means is operably connected to the control means of said milking apparatus. Hereby is achieved

a possibility of automatically performing a milking operation.

Advantageously, said milking unit is adapted to be moved together with a robot arm in relation to an animal, said robot arm being operable by said control means in response to said viewing means for enabling proper attachment of said teatcup to a teat of said animal.

Preferably, said control means is adapted to commence and interrupt a milking operation regarding said teatcup, in response to said viewing means. Hereby a teatcup may be detached and reattached in case it has been incorrectly attached, e.g. if the teat has been folded during attachment. The teatcup may also be detached n case of a ceasing milk flow or when a teat has been established to be injured or when the liner of the teatcup has been established to be damaged.

Preferably, a teatcup -cleaning means is operable by said control means for cleaning of said teatcup in response to said viewing means. Hereby, a detected dirty chamber of the teatcup may be cleaned.

Advantageously, said teatcup is connectible to a milk line and wherein a milk line cleaning means is operably connected to said control means for cleaning of at least a part of said milk line. Hereby the milk line may be cleaned in case of detected dirt, milk residues or blood in the milk line or in the extracted milk.

Advantageously, a signal transmitter is operably connected to said control means for transmitting a signal to an attention bringing means in response to a signal from the viewing means. Hereby, a damaged liner may be exchanged at an early time point, or an animal's teat suffering from an

injury or a malady may be quickly treated. The injury or malady may be established e.g. by checking for blood in the milk depending on an injury inside or outside the teat or the udder; an abnormal colour of the teat depending on a malady, such as a disturbed blood circulation in the teat; or an abnormal direction or spread of the milk jet during milking at the vicinity of the teat orifice depending on a deformation of the teat at the teat orifice as a consequence of e.g. an incautious step by the animal on its own teat.

Preferably, said method includes establishing by said viewing of the chamber the existence of a correctly positioned teat in the chamber of said teatcup, and starting a milking operation by means of said control means. Hereby a safer milking operation is achieved, since milking of all quarters of the udder is secured.

Advantageously, the method includes establishing by said viewing of the chamber the existence of a milk flow in the chamber of said teatcup.

In case said established milking related condition is a folded teat, the teatcup is detached from the teat as a consequence thereof and reattaching it thereafter to the teat, by means of a robot arm. Hereby, "blind milking" of the teat is avoided.

Advantageously, said method includes controlling said milking apparatus to interrupt a milking operation at least regarding said teatcup, in response to said established milking related condition, and to remove said teatcup from the teat.

In case said established milking related condition is a ceasing milk flow from said teat into the chamber of said teatcup, said milking operation is interrupted as a

consequence thereof. Hereby is achieved an improved way of interrupting milking of each teat, since too long milking of a teat may cause mastitis.

In case said established milking related condition is a dirty teat, the teatcup is detached from the teat as a consequence thereof. The teat is thereafter cleaned by means of a teat cleaning means. Subsequently, the teatcup is re-attached onto said teat by means of a robot arm. Hereby, the risk for introduction of dirt into the extracted milk is avoided.

The method may also include establishing, as said milking related condition, that at least a part of a surface delimiting said chamber, is dirty.

In case the established milking related condition is an undesired substance in the milk extracted from said teat, the teatcup is detached from the teat as a consequence thereof. The extracted milk is returned through the teatcup in a direction, which is opposite to the flow direction of milk during milking, and is let out through an opening, which is adapted to receive a teat during milking.

Preferably, said teatcup is cleaned by switching a valve from a milking mode to a teatcup cleaning mode, thereby allowing a cleaning liquid to flow from a cleaning means to said teatcup in a direction, which is opposite to the flow direction of milk during milking, and to be let out through an opening, which is adapted to receive a teat during milking.

Advantageously, said method includes establishing, as said milking related condition, the existence of a cleaning liquid in the chamber of said teatcup.

Preferably, the method includes establishing, as said milking related condition, a predetermined level of cleanliness of said cleaning liquid and interrupting the flow in response thereto.

In case said established milking related condition is malfunction of said teatcup liner, the teatcup is, as a consequence thereof, detached from said teat. The malfunction may be an abnormal movement of the liner due to abnormal pressure differences in the pulsating vacuum, cracks in the liner, or a non-sealingly mounted liner or vacuum tube.

In case said established milking related condition is a bad condition of said teat, the teatcup is, as a consequence thereof, removed from the teat.

Preferably, said method includes establishing, as said milking related condition, data regarding the shape and/or colour of an animal individual s teats, respectively, storing said data, and using said data as reference while establishing the condition of said teat. In order to allow comparing of historical data of an animal individual to present data, a transponder carried by each animal individual may be used for revealing its identification.

In such cases, it is preferable that a further signal is transmitted from said control means by means of a signal transmitting means to an attention bringing means, as a consequence of said establishment of a milking related condition. Said attention bringing means may be a mobile buzzer carried by a person, a mobile telephone, a bell, a flash light or the like.

A signal may also be transmitted to the attention bringing means in case repeated non-existence of a milk flow is

established, either at the same milking occasion or after a plurality of milking occasions in a row.

In addition to or as an alternative to transmitting a signal to the attention bringing means, the animal may be separated from the herd by opening a separation gate leading to a separation area by means of said control means, in response to said viewing means, having established said milking related condition.

DRAWING SUMMARY

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings in which:

Figures la, lb, lc and Id illustrate schematically alternatives of a milking unit according to a first embodiment of the invention, respectively;

Figure 2 illustrates schematically a milking unit according to a second embodiment of the invention;

Figures 3a and 3b illustrate schematically alternatives of a milking unit according to a third embodiment ' of the invention;

Figure 4 illustrates schematically a milking apparatus provided with a milking unit according to the first or the second embodiment.

Figure 5 illustrates schematically a milking apparatus provided with a milking unit according to the third embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Figure la shows a milking unit 1 according to a first embodiment of the invention, comprising a teatcup 2 provided with a shell 3 and a flexible liner divided into an upper and a lower part 4a, 4b and defining an upper and a lower space 5a, 5b connected via lines 6a, 6b to a source (not shown) of alternative pressures, such that during milking, the upper space 5a is subjected to a higher pressure than the lower space 5b and vice versa. A teatcup of this kind is disclosed in EP-A-0 266 809.

The upper and lower parts 4a, 4b of the liner and a part Of the shell 3 between the parts 4a and 4b delimit a chamber 7 to be viewed by a viewing means 8 comprising a lens 9. The teatcup is furthermore provided with a milk tube 10, the interior of which is connected to one end of said chamber 7. The upper part 4a of the liner is provided with an opening 7a for allowing 'a teat to be introduced into the chamber 7.

Figures lb to Id show alternative milking units 1 according to the first embodiment of the invention. The teatcup 2 is provided with a shell 3 and a single liner 4, delimiting thembetween a space 5 connected to a source of alternating pressures via line 6, such that during milking, the space 5 is subjected to two different; alternating pressures, e.g. vacuum and atmospheric pressure.

In the milking units of figures lb - Id, the liner 4 itself delimits the chamber 7.

In the milking unit according to figure la, the lens 9 is arranged right inside the shell 3. The lens 9 is connectible to a control means (cf. figure 4) via a fibre optic cable 11, extending through the shell 3. A light source 11a is arranged in connection with the fibre optic cable 11. Light

may thus be transferred through the cable 11 in order to illuminate the chamber 7. Hereby, viewing of the chamber 7 through the lens 9 and the fibre optic cable 11 is possible during bad light conditions.

In the milking unit according to figure lb, the lens 9 is arranged at the interior surface of the liner 4 in the chamber 7. The cable 11, which is associated with a light source 11a, extends through the space 5. In the milking unit of figure lc, however, the lens 9 is arranged m the milk tube 10 and is directed towards the chamber 7.

In the milking unit of figures la to lc, the milk tube 10 extends vertically from the chamber 8. In the milking unit of figure Id, however, the milk tube 10 extends substantially perpendicularly from an end of the chamber 7 via a connection part 12, which interconnects the teatcup 2 and the tubes 6 and 10. This arrangement allows for a simple exchange, repair and cleaning of the viewing means.

In figure 2, a second embodiment of the invention is shown, wherein the lens 9 of the viewing means 8 is arranged in the space 5 at the interior surface of the shell 3. The cable 11 extends through the shell 3 to the exterior, where it is associated with the light source 11a.

In order to allow viewing of the chamber 7, the liner 4 is transparent or transparent in part. By transparent in part is meant that the liner is made of a semi-transparent material or consists partly of non-transparent material and partly of transparent material. The latter may be performed by providing a non-transparent liner with a plurality of transparent "windows" in the form of squares, circles, stripes or the like.

Figures 3a and 3b show, respectively, a milking unit according to a third embodiment of the invention. The whole viewing means 8 in the form of a camera, e.g. a video camera, is provided outside the teatcup 2 on a suitable support 13.

The teatcup according to figure 3a corresponds to the one of figure lb. In order to allow viewing of the chamber 7, the liner 4 as well as the shell 3 is transparent or transparent in part (cf. above in connection with figure 2 the discussion regarding the expression "transparent in part") . The light source 11a is in this case a lamp arranged on the support 13, which illuminates the chamber 7 from the exterior of the teatcup 2.

The teatcup according to figure 3b corresponds to the one shown in figure la. In this case, it is immaterial whether the upper part 4a or the lower part 4b of the liner is transparent or not, as long as the part of the shell 3, which delimits the chamber 7 is transparent or transparent in part (cf. above) . Of course, also the liner parts 4a and 4b may be transparent or transparent in part, if desired. The light source 11a is shown as a light diode connected to the exterior of the teatcup 2 by means of an electric cable 11.

Of course, the light source of figure 3a may be placed in relation to the teatcup as shown in figure 3b, and vice versa.

Figure 4 shows a milking apparatus provided with a milking unit 1 according to the first or the second embodiment of the invention. The milking apparatus comprises a support 13 in the form of a robot arm with a teatcup holder 14 for attachment of a teatcup 2 onto a teat 17 of an udder 18. The

fibre optic cable 11 of the viewing means is connected to a control means 15, which in turn is connected via a cable 16 to the robot arm 13. The image transferred via the fibre optic cable 11 is analysed in the control means 15 and is used as basis for control of the movement of the robot arm 13.

The milk tube 10 is connected to a valve 19, which is automatically switchable - in response to a signal from the control unit 15 via a wire 20 - from a milking mode (MM) , such that the milk tube is connected to a milk line 21, to a teatcup cleaning mode (TCM) , such that the milk tube is connected to a cleaning tube 22. The cleaning tube is in turn connected to a washing unit 23. A washing unit of this kind is sold by Alfa Laval Agri Inc., USA, under the trademark Autoflush Backflush System, which washing unit cleans the milk tube and the teatcup by flushing a cleaning liquid from the washing unit 23 through the cleaning tube 22, the valve 19, the milk tube 10 and the chamber 7 of the teatcup 2. The liquid is let out through the opening 7a. Also the washing unit 23 is controlled by the control unit 15.

The valve 19 is also switchable to a milk line cleaning mode (MCM) , in which the milk line 21 is connected to the wash unit 23, for allowing cleaning of the milk line 21.

A teat cleaning means 24 in the form of two counter-rotatable cylindrical brushes is provided for cleaning of the teats, if needed. It may be brought to the teats 17 by means of the robot arm 13 or a separate robot arm.

A signal transmitter 25 is connected to the control means 15 for calling the attention of a person carrying a receiver 26

in the form of a buzzer, a mobile telephone a bell or the like. Of course, a buzzer or a bell may be directly connected to the control means 15.

A teatcup tray 27 carrying a plurality of teatcups is arranged within reach of the robot arm 13, for allowing easy consecutive attachment of a teatcup to each of the teats of the udder of the animal.

Figure 5 shows a milking apparatus provided with a milking unit 1 according to the third embodiment. The viewing means 8 is connected to the control means 15 via a wire 28 for allowing transfer of a signal regarding the received image to the control means 15.

The illuminating means 11a is a lamp, the light of which is transferred to the interior of the teatcup by means of the fibre optic cable 11. Of course, the alternatives for illumination thereof as shown in figures 3a and 3b are possible. Moreover, it is to be noted that the illuminating means 11a may as an alternative comprise a flash light illuminating the teatcup or the interior of the teatcup for a short period of time. Thus, it is not necessary to continuously illuminate the teatcup or interior thereof. Furthermore, a series of flashes may occur at a high frequency as a stroboscope light source.

FUNCTION

The teatcup 2 of the milking unit 1 according to the invention may before use be checked by said viewing means 8 regarding the cleanliness of the chamber 7, i.e. the interior surfaces of the teatcup 2 and/or the liner 4. If the control means 15 establishes by e.g. colour analysis, such as Red-Blue-Green (RBG) -analysis, existence of dirt, blood or the like in the chamber, the control means 15

switches the valve 19 to the teatcup cleaning mode (TCM) . The teatcup is then automatically flushed by a cleaning liquid. After the cleaning operation, the valve 19 is switched to the milking mode (MM) . If the control means 15 establishes a damaged teatcup liner 4 or teatcup 2, the signal transmitting means 25 is controlled by the control means 15 to transmit a signal to a buzzer 26 or the like, carried by a milk maid.

The teatcup is now ready for attachment onto a teat of an animal to be milked, such as a cow, a sheep, a goat, a buffalo or a horse. This may be performed manually or by means of a robot arm 13. In the latter case, a suitable sensor, such as a laser sensor or an ultrasonic sensor, is needed to find the teats of the animal. However, the video camera 8 shown in figure 5 may be used also for this purpose.

A correctly attached teatcup is established by viewing the chamber 7 by means of the viewing means 8 and analysing the received image in the control means 15 by e.g. RBG-analysis. It is also possible to establish a correctly attached teatcup by analysing the change of the light contrast or the light intensity sensed by the viewing means 8.

It is previously known to check whether a teatcup is attached to a teat by establishing whether a change of pressure in the teatcup chamber, subjected to a vacuum, has occurred. However, if the teatcup has become attached to the side of the udder or if the teat has become folded in the teatcup opening, a change of vacuum will occur also in this case.

However, by means of the milking unit according to the invention, an incorrect attached teatcup is possible to establish by viewing the teatcup chamber 7, since if the

teatcup is incorrectly attached, a teat will not be visible in the chamber 7. If this is the case, the robot arm 13 is controlled by the control means 15 to detach the teatcup and to reattach the teatcup onto the teat until a correctly attached teatcup has been established.

If the teat in the chamber 7 is established to be dirty, the teatcup 2 is detached from the teat and the teat is cleaned by means of the teat cleaner 24. Since the teat may have contaminated the chamber of the teatcup, even though not visibly, it may be preferable to allow the chamber to be cleaned as well, by switching the valve to the teatcup cleaning mode (TCM) by means of the control means 15 and allowing a rinse fluid from the washing unit 23 to flush the teatcup 2. After finished cleaning, the valve 19 is switched to the milking mode (MM) by means of the control means 15.

When a correctly attached teatcup has been established, the occurrence of a milk flow is detected, e.g. by RBG-analysis. If no milk flow is established, the teatcup should be detached and reattached. If a milk flow can still not be established, the signal transmitting means 25 is controlled by the control means 15 to transmit a signal to a buzzer 26 or the like, carried by the milk maid.

The viewing means 8 may also detect a ceasing milk flow from a teat, i.e. an udder quarter. In response to this, the control means 15 detaches the teatcup 2 from the teat. This sequence will be performed for each connected teatcup.

The detachment of the teatcups after finished milking may be performed either by the robot arm or by a standard teatcup removal means in the form of one or several ropes connected at one end to one or several teatcups and at the other end to e.g. an air motor.

After detachment, the control means 15 switches the valve 19 to the teatcup cleaning mode (TCM) in order to clean the milk tube 10 and the teatcup 2 by flushing a cleaning liquid therethrough. This may be performed by flushing each detached teatcup 2 after it has been detached. In this case, one valve 19 is needed per milk tube 10.

Alternatively, the teatcups are flushed simultaneously after all the teatcups have been detached from the udder. Even though one valve per milk tube may be used also in this case, it is contemplated that each milk tube 10 may be connected to a single valve 19, either directly or via a milk claw (not shown) .

After each milking or several milkmgs, the milk line 21 may be cleaned by switching the valve 19 to the milk line cleaning mode (MCM) . After finished cleaning, the valve 19 is switched to the milking mode (MM) by means of the control means 15.

The invention is not limited to the embodiments described above. Consequently, a plurality of milking units according to the invention may be brought simultaneously to the teats of the animal, by means of one or several robot arms.