Apparatus for applying at least one teat cup to a teat of an animal

An apparatus for applying at least one teat cup (1) to a teat (2) of an animal (3), which includes a sensor arrangement (5) which has at least one sensor unit (6) that can be brought into contact with a rear body part of the animal (3). To apply a teat cup, an application device (14) is provided, which comprises at least one positioning arm (15) for applying the at least one teat cup (1) to the teat (2) of the animal (3). The application device is coupled with a controller, which connects to a positioning device. The sensor arrangement (5) comprises a measuring device (9) connected to the sensor unit (6). The sensor arrangement (5) is stationarily arranged with respect to a reference position. The sensor unit (6) is designed and constructed such that it follows the movement of the animal (3), and the measuring device (9) measures the change of position of the sensor unit (6) with respect to the reference position. The measuring device connects to an evaluation unit of a controller, so that the data obtained by the measuring device are used for a coarse positioning of the positioning arm (15).

BACKGROUND OF THE INVENTION
 The subject matter of the present invention relates to an apparatus for
 applying at least one teat cup to a teat of an animal, in particular a
 cow.
 For mechanically applying at least one teat cup to a teat of an animal, in
 particular a cow, a large variety of configurations of such apparatus have
 been developed. EP 0 300 115 B1 discloses an apparatus for applying at
 least one teat cup to a teat of an animal, which comprises sensors for
 locating the position of the teat as well as a movable positioning arm for
 applying at least one teat cup. The location of at least one teat occurs
 such that a sensor unit initially performs a coarse positioning of the
 positioning arm. Thereafter, additional sensors perform a fine positioning
 of the positioning arm. Once the teat is found, the teat cup is applied.
 The sensors may be ultrasound sensors or optical sensors. Since the sensors
 are arranged within a reach of contamination, there is the risk that
 contamination reduces the sensitivity of the sensors, so that more time is
 required for locating a teat.
 EP 0 191 517 B1, EP 0 258 938 B1, as well as EP 0 551 960 B1 disclose
 apparatus for applying at least one teat cup. These apparatus are intended
 to facilitate a coarse positioning of the positioning arm in that the
 freedom of movement of the animal in a milking compartment is reduced by
 blocking means. The animal occupies in the milking compartment a
 predetermined, forced position, which the animal is unable to change while
 at least one teat is being located. This forced position of the animal in
 the milking compartment may lead to a decrease in the milk output of the
 animal, since the animal is exposed by its forced position in the milking
 compartment to an increased stress situation.
 EP 0 630 564 A2 discloses an apparatus for applying at least one teat cup,
 which comprises a sensor arrangement with at least one sensor unit adapted
 for contacting a rear body part of the animal. The sensor unit extends in
 the longitudinal direction of the milking compartment and is thus
 displaceable in the longitudinal direction of the animal, so that the
 animal is able to move inside the milking compartment. The sensor
 arrangement follows the movement of the animal. The positioning arm is
 rigidly connected to the sensor arrangement via a frame. The positioning
 arm is forced to follow the movement of the sensor arrangement. The sensor
 arrangement is arranged on a crossarm, which is adapted for swiveling
 about a substantially vertically extending axle. To make it possible for
 an animal to enter the milking compartment, it is necessary to swing the
 crossarm out of the milking compartment. This requires adequate space for
 being able to perform the swinging motion.
 Based on the foregoing, it is an object of the present invention to improve
 the known apparatus for applying at least one teat cup such that a coarse
 positioning of the positioning arm is simplified.
 SUMMARY OF THE INVENTION
 The above and other objects and advantages of the present invention are
 achieved by the provision of an apparatus for applying at least one teat
 cup to a teat of an animal, in particular a cow, which comprises a sensor
 arrangement, which includes at least one sensor unit. The sensor unit is
 adapted for coming into contact with a rear body part of the animal. The
 apparatus also comprises an application device, which includes at least
 one positioning arm for applying at least one teat cup to a teat of the
 animal and a positioning device for locating at least one teat and for
 positioning the positioning arm. Furthermore, the apparatus comprises a
 controller that connects to the positioning device.
 The sensor arrangement comprises a measuring device connected to the sensor
 unit. The sensor arrangement is stationarily arranged with respect to a
 reference position. However, the sensor unit is adapted for changing its
 position along with the movement of an animal. The measuring device
 measures a change of position of the sensor unit with respect to the
 reference position. The measuring device connects to the controller, which
 includes an evaluation unit. In the evaluation unit, the measurement is
 evaluated, which has been carried out by the measuring device. The result
 of the evaluation is used for a coarse positioning of the positioning arm.
 Between the sensor arrangement and the positioning device, in particular
 the positioning arm, there is no mechanical connection, so that the sensor
 unit is movable independently of the positioning arm. Contrary to the
 disclosure of EP 0 630 564 A2, it is thus made possible to realize a
 greater capability of the sensor unit responding to possible movements of
 the animal. Since the positioning arm does not mechanically connect to the
 sensor unit, lesser masses are to be moved.
 According to an advantageous embodiment of the apparatus according to the
 invention, it is proposed to adapt the sensor unit for pivoting movement
 about an axle. Preferably, the sensor unit is pivoted about a
 substantially horizontally extending axis which is defined by the axle. In
 this connection, the substantially horizontally extending axis is arranged
 preferably such that it is located at a distance spaced above the floor.
 With this arrangement, it is also accomplished that dirt-sensitive parts
 of this sensor arrangement are arranged outside of the reach of dirt. The
 fact that the axis extends horizontally and at a distance above the floor
 simplifies access of an animal to a milking compartment, since it is
 possible to swing the sensor arrangement upward out of the milking
 compartment, thereby reducing likewise the space requirement. In addition
 to a horizontally extending axis, the sensor unit may also be adapted for
 pivoting about a substantially vertically extending axis, thereby
 permitting further improvement in the accuracy of the coarse positioning
 of the animal within a milking compartment.
 Preferably, the apparatus of the present invention is constructed with a
 sensor unit that comprises at least one substantially bar-shaped scanning
 element. Preferred, however, is an apparatus, wherein the sensor unit is
 formed by a U-shaped bracket. The U-shaped bracket ensures that the sensor
 unit can also be reliably brought into contact with a rear body part of
 the animal. The U-shaped bracket also permits transmitting in a relatively
 simple manner a deflection of the sensor unit about a substantially
 vertically extending axis.
 According to a yet further advantageous embodiment of the apparatus, it is
 proposed to provide the bracket with legs, which connect to the axle.
 Preferably, the legs are constructed substantially parallel to each other.
 The spacing between the legs is smaller than an inside width of a milking
 compartment.
 The measuring device preferably is an angle measuring instrument, which
 measures a deflection of the sensor unit about the pivoted axis.
 Preferably, the angle measuring device is a digitally operating angle
 measuring instrument, so that the digital signals of the angle measuring
 instrument can be supplied to the evaluation unit of the controller. In
 the evaluation unit, the relative position of the animal with respect to
 the reference position is determined on the basis of the measured
 deflection of the sensor unit.
 The measuring device may also be a displacement measuring device, which
 measures a distance, by which the sensor unit is deflected from the
 reference position. The displacement measuring device may be, for example,
 an inductively operating displacement measuring device.
 According to a yet further advantageous embodiment of the apparatus, it is
 proposed to provide the sensor arrangement with an actuation unit, which
 connects to the sensor unit in such a manner that the sensor unit lies
 against a rear body part of the animal with a predetermined force. The
 force is selected such that the animal does not negatively respond to the
 contact of the sensor unit. The sensor unit contacts the animal under the
 predetermined force even during a movement of the animal.
 Preferably, the actuation unit is connected to the axle. To keep the moment
 necessary for bringing the sensor unit into contact with a rear body part
 of the animal as small as possible, it is proposed to connect the
 actuation unit to the axle via a lever.
 A hydraulically or pneumatically operating piston-cylinder unit may form
 the actuation unit. Preferably, the actuation unit is a pneumatically
 operating piston-cylinder unit. In particular, it is proposed to provide
 the piston-cylinder unit with a piston that can be biased on both sides by
 a pressure medium, so that the force, under which the sensor unit lies
 against the rear part of the animal body, can be kept constant during a
 movement of the animal.
 The actuation unit may also be an electromotive unit, or it may be formed
 by at least one spring, preferably a tension spring, so that the sensor
 unit comes into contact with the rear part of the animal body.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
 FIG. 1 is a schematic view of an apparatus for applying at least one teat
 cup 1 to a teat 2 of an animal 3. The animal 3, which is in the
 illustrated embodiment a cow, is shown in a milking compartment 4. The
 milking compartment 4 is constructed in a manner known per se.
 The apparatus comprises a sensor arrangement 5. The sensor arrangement 5
 includes a sensor unit 6 that can be brought into contact with a rear body
 part of the animal 3. The sensor unit is adapted for pivoting about a
 substantially horizontally extending axis which is defined by an axle 7.
 The axle 7 is supported on an upper beam 8 of the compartment 4, so that
 the pivotal axis is above the height of the animal. The sensor unit 6
 connects to a measuring device 9, which comprises an angle measuring
 instrument which measures a deflection of sensor unit 6 about the axis of
 the axle 7 with respect to a reference position. Preferably, the measuring
 device 9 is a digitally operating angle encoder. The measuring device 9 is
 arranged at an elevated location so as to be outside a reach of dirt and
 water.
 Connected to axle 7 is a lever 10, which is engaged by an actuation device
 11. In the illustrated embodiment, the actuation device 11 is a
 pneumatically operating piston-cylinder unit, which includes a cylinder 13
 which is pivotally joined to the beam 8. A piston rod 12 extends from the
 cylinder 13 and connects with its free end to the lever 10. When the
 actuation unit is biased by a pressure medium, the sensor unit 6 will
 pivot via lever 10 about axle 7 in a direction towards the rear body part
 of animal 3. The pivoting procedure will end only, when the sensor unit 6
 lies under a predetermined force against the body of animal 3. During a
 movement of animal 3, the actuation unit 11 will cause sensor unit 6 to
 follow, when the force decreases, which is operative between the sensor
 unit 6 and the body part of animal 3. The force, which the sensor unit 6
 applies to the animal even during a movement of the animal inside the
 milking compartment, is preferably constant. To this end, the pressure of
 the medium of the piston-cylinder unit is changed in corresponding manner.
 Preferably, the pressure inside the piston-cylinder unit for swinging the
 sensor unit out of a milking compartment may be increased such that the
 sensor unit can be moved out of the milking compartment relatively
 quickly. Also, the actuation unit may be biased in the opposite direction
 by the increased pressure until the sensor unit comes into contact with
 the animal, and thereafter it is biased by a reduced pressure.
 The measuring device 9 connects by means of a control line to an
 application device 14. The application device 14 comprises a positioning
 device 17 (FIG. 2) for locating at least one teat. This positioning device
 performs a fine or very accurate location of the teat. The application
 device 14 comprises at least one positioning arm 15, which mounts the at
 least one teat cup 1 that is to be positioned.
 FIG. 2 is a schematic circuit diagram. The application device 14 comprises
 a controller 16, which serves to activate a drive 18. The drive 18 causes
 the positioning arm 15 to adapt to the position of the animal.
 The measuring device 9 connects by means of a control line to the
 controller 16. The controller 16 includes an evaluation unit 19, which
 evaluates the results measured by measuring device 9. The measurement,
 which is performed by measuring device 9 may proceed continuously or
 within predetermined time intervals. In particular, the evaluation unit 19
 determines the distance of the rear body part of animal 3 with respect to
 a reference position. The result of the evaluation by the evaluation unit
 is used for a coarse positioning of positioning arm 15. For a fine
 positioning of the positioning arm, the positioning device 17 is provided,
 which connects to controller 16.
 FIG. 3 illustrates an embodiment of a sensor unit 6. The sensor unit 6 is
 in the form of a bracket having legs 20 which are connected to axle 7. The
 distance between the substantially parallel extending legs is smaller than
 the width of the milking compartment 4. The sensor unit 6 is adapted for
 pivoting about the horizontal axis of the axle 7, so that it opens the
 milking compartment 4 for the entry of an animal.
 Many modifications and other embodiments of the invention will come to mind
 to one skilled in the art to which this invention pertains having the
 benefit of the teachings presented in the foregoing descriptions and the
 associated drawings. Therefore, it is to be understood that the invention
 is not to be limited to the specific embodiments disclosed and that
 modifications and other embodiments are intended to be included within the
 scope of the appended claims. Although specific terms are employed herein,
 they are used in a generic and descriptive sense only and not for purposes
 of limitation.