EP1928229A2

EP1928229A2 - Apparatus for processing feed for cattle

Info

Publication number: EP1928229A2
Application number: EP06783942A
Authority: EP
Inventors: Cornelis Hendricus Liet
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-08-30
Filing date: 2006-08-08
Publication date: 2008-06-11
Also published as: WO2007037693A2; WO2007037693A3; NL2000173C2

Abstract

An apparatus for processing feed for cattle comprises a container (1) having a bottom (2) and an upstanding wall (3) and at least one mixing element (8) , which is rotatably mounted in the container about a shaft (10) that extends upwards from the bottom thereof, and which can be coupled to a drive unit. The mixing element comprises an upper part (16) and a lower part (17) , whilst means are provided for rendering the lower part of the mixing element inoperative.

Description

Apparatus for processing feed for cattle

The invention relates to an apparatus for processing feed for cattle, which apparatus comprises a container having a bottom and an upstanding wall and at least one mixing element, which is rotatably mounted in the container about a shaft that extends upwards from the bottom thereof, and which can be coupled to a drive unit .

Such an apparatus is known in various embodiments thereof. Usually, one or more bales of feed are deposited into the container, after which the mixing element is rotata- bly driven by the drive unit for the purpose of reducing the bale or bales and mixing the feed. The known apparatus requires a high power level for driving the mixing element, because the mixing element engages the bale/bales over the entire height of the vertical shaft for reducing the bale or bales. At least substantially the entire weight of the bale or bales is lifted by the lower part of the mixing element during said operation. If the cargo is transported over a large distance, the cargo will compact, so that the initial torque that is required will be even higher. Usually the drive unit of the apparatus comprises a shaft mounted under the bottom of the container, which shaft can be coupled to the vertical shaft of the mixing element, which former shaft can be coupled to the power take-off shaft of a tractor. This means that a very powerful tractor is needed for driving the mixing element of the known apparatus.

The object of the invention is to provide an apparatus of the above kind, wherein less power will suffice for driving the mixing element.

According to the invention, the apparatus is to that end characterised in that the mixing element comprises an upper part and a lower part, while means are provided for rendering the lower part of the mixing element inoperative.

In this way an apparatus is obtained in which it is possible to put only part of the mixing element, preferably the upper part, into operation, so that only the activated part will be operative for reducing and mixing the bale or bales and mixing the material of the bale/bales with any feeds that are separately added. The mixing element need not lift the entire weight of the bale/bales. As a result, a relatively low power level will suffice. Once the bale/bales have been reduced, both parts of the mixing elements are put into operation and the entire contents of the container are mixed within a short period of time. According to a first embodiment of the invention, the upper part and the lower part can each be coupled to the drive unit. As a result, one part or both parts can be separately coupled to the drive unit, or one part can be coupled to the drive unit via the other part, and the lower part can be rendered inoperative in a simple manner by coupling only the upper part to the drive unit . Once the feed has been reduced to a sufficient degree, the lower part may be coupled to the drive unit as well.

Preferably, the upper part can be coupled to the drive unit separately from the lower part, and once the bale or bales has (have) been reduced by the upper part, the lower part of the mixing element can be coupled to the upper part so as to be driven by the drive unit. When both parts of the mixing element are in operation, the entire contents of the container are mixed.

According to an alternative embodiment of the invention, the lower part of the mixing element comprises one or two blades, each blade being movable between an operative position, in which the blade extends upwards, and an inopera- tive position, in which the blade extends substantially horizontally. The lower part can readily be rendered inoperative in that case by placing the blade or each blade in the position of rest.

According to the invention, the mixing element may be configured as a mixing screw provided with a helically extending blade comprising a blade portion that is movable between an inoperative position, in which the blade portion is retracted, being positioned at least partially within the circumference of the blade positioned thereabove, and an operative position, in which the blade portion projects further beyond the circumference of the higher helical blade.

According to a very advantageous embodiment of the invention, the vertical shaft of the mixing element is pivot- mounted in the container. Pivoting of the vertical shaft jen- ables an efficient processing of the feed that has been deposited into the container, wherein the feed can be significantly reduced by moving the vertical shaft towards the wall. In addition, said pivoting of the vertical shaft will result in an improved mixing action of the mixing element.

According to the invention, it will be advantageous if the pivoting path extends at least substantially in the longitudinal direction of the container. The invention also provides a mixing element for the apparatus as described above, which mixing element according to the invention comprises an upper apart and a lower part, whilst means are provided for rendering the lower part of the mixing element inoperative. The invention will be explained in more detail hereinafter with reference to the drawing, in which a few embodiments of the apparatus according to the invention are shown schematically.

Fig. 1 is a schematic side view of a first embodi- ment of the apparatus according to the invention, in which a part of the container is shown in cutaway view.

Fig. 2 is a top plan view of the apparatus according to Fig. 1.

Fig. 3 is a larger-scale view of the detail III of Fig. 1.

Fig. 4 is a top plan view corresponding to Fig. 2 of a second embodiment of the apparatus according to the invention.

Fig. 5 shows a detail of an alternative embodiment of the apparatus according to the invention that corresponds to the detail III of Fig. 1. Fig. 6 is a schematic side view of a mixing element of an alternative embodiment of the apparatus according to the invention.

Fig. 7 is a larger-scale bottom plan view of a part of the mixing element of Fig. 6.

Figs. 8 and 9 are a top plan view and a side vijsw, respectively, of an alternative embodiment of a mixing element according to the invention.

Figs- 10 and 11 are views of another embodiment of the mixing element according to the invention that correspond to the views of Figs. 8 and 9.

Figs. 12 and 13 are views of yet another embodiment of the mixing element according to the invention.

Fig. 14 is a schematic side view of a mixing ele- ment of an alternative embodiment of the apparatus according to the invention.

Fig. 15 is a partial top plan view of the lower par.t of the mixing element of Fig■. 14. .

Fig. 16 is a view of a part of figure 14 along the line XVT-XVI, in which the blade is shown in the operative • position.

Fig. 17 is a view corresponding to Fig. 16, in which the blade is shown in the inoperative position.

Figs. 18 and 19 are a side view and a top plan view of another embodiment of the apparatus according to the invention .

Fig. 20 is a schematic side view of another embodiment of the mixing element according to the invention, in which a blade portion is movable between an inoperative posi- tion and an operative position.

Figs. 21 and 22 are top plan views of the mixing element of fig. 20 in the inoperative position and in the operative position, respectively.

Figs. 23A and 23B are a top plan view and a side view, respectively, of yet another embodiment of the mixing element according to the invention.

Fig. 24 is a very schematic view of an embodiment of the mixing element according to the invention. Figs. 1 and 2 are a very schematic side view and a very schematic top plan view, respectively, of an apparatus for processing feed for cattle, which apparatus comprises a container 1 having a bottom 2 and an upstanding wall 3. The container 1 is mounted on a mobile chassis 4 comprising an axle fitted with wheels 5, one of which is shown in Fig. JL . The chassis 4 comprises a drawbar 6, by means of which the apparatus can be coupled to a tractor (not shown) . Two mixing elements 7 and 8 are disposed in the container 1 of the appa- ratus described herein, which mixing elements are rotatable about vertical shafts 9 and 10, respectively. The shafts 9,10 can be driven via a connecting shaft 11 mounted under the bottom 2 of the container 1, which can be connected to the power take-off shaft of the tractor (not shown) with an end 12 thereof. The connecting shaft 11 can be connected to the vertical shafts 9 and 10 via right-angled gearboxes 13,14, which can be jointly or individually engaged for putting the mixing elements 7,8 into operation.

As appears from Figs. 1 and 2, the mixing elements 7,8 are configured as so-called mixing screws provided with a helical mixing blade 15. According to the invention, the mixing screw 8 consists of two parts, an upper part 16 and a lower part 17. The lower part 17 comprises one or two blades 18 and the upper part 16 supports the helical mixing blade 15. The mixing screw 7 likewise comprises one or two blades 18 and the mixing blade 15, which are all connected to the same shaft 9. The lower part 17 can be rendered inoperative in a simple manner, using suitable means yet to be described hereinafter, so that only the upper part 16 will be in opera- tion for a desired period of time for reducing the bale or bales of feed.

In the embodiment that is shown in Figs. 1 and 2, the vertical shaft 10 of the upper part 16 of the mixing element 8 is moreover capable of pivoting movement in the container 1 because said vertical shaft is connected, by means of a universal joint 19 (shown schematically in Fig. 3), to a shaft end 20 that extends upwards from the gearbox 14. The universal joint 19 is accommodated in a closed hous- ing comprising two spherical members 21,22 that fit together, wherein the spherical member 21 is connected to the vertical shaft 10 and the spherical member 22 is connected to the shaft end 20 in the embodiment of Fig. 3. The upper part 16 of the mixing element 8 can be pivoted along a path 24 that extends at least substantially in the longitudinal direction or direction of movement of the container 1 by means of an actuating unit 23. In the embodiment that is shown in Figs. 1-3, the actuating unit 23 comprises a coupling arm 25 mounted between the upper end of the vertical shaft 10 and the wall 3 of the container 1, with a hydraulic cylinder-piston assembly 26 being provided between the coupling arm 25 and the wall 3 of the container 1. Oil can be supplied to the cylinder-piston assembly 26 in various ways for effecting the pivoting movement of the vertical shaft 10. According to one possibility, for example, an oil pump is mounted in the upper end of the vertical shaft 10, which pump supplies oil to the cylinder-piston assembly 26 via a reversing valve. Alternative constructions are pos- sible, of course.

An important advantage of the apparatus comprising, a mixing screw 8 consisting of two parts 16,17 as described herein is that a relatively low-horsepower tractor will suffice for the processing of feed. Using the apparatus described herein, one or more bales of feed are deposited into the container 1, and initially only the upper part 16 of the mixing screw 8 is put into operation for reducing the bale or bales, so that the lower part 17 remains inoperative. Said upper part 16 is driven by driving the vertical shaft 10 from the power take-off shaft of the tractor (not shown) via the connecting shaft 11, the gearbox 14 and the shaft end 20. A coupling 28 (yet to be described hereinafter) between the shaft 10 of the upper part 16 and the lower part 17 of the mixing screw is not operative yet in this situation. As a re- suit, only the upper part 16 is driven, which upper part reduces the bale or bales. The advantage of this is that the mixing screw 8 engages the bale or bales only along part of its height, so that less power is required for reducing the bales. The lower part 17 provided with the blades 18 is not operative in this situation, so that said blades need not lift the bale or bales.

In the described embodiment shown in Figs. 1-3, the actuating unit 23 can be activated as well, so that the upper part 16 will pivot along the path 24, resulting in an im^ proved reducing action and an improved mixing action of the mixing screw 8, in particular in the longitudinal direction of the container 1. As the top plan view of Fig. 2 shows, the operating unit 23 can move the vertical shaft 10 towards the oval (in this case) rear end 27 of the wall 3 of the container 1, thereby reducing the passage between said rear end 27 and the mixing screw 8. The direction of rotation of the mixing screw 8 is such that the material of the bale/bales is pressed in the direction of said passage and thus against the edge of the mixing blade 15, so that an effective reduction of the bale/bales is ensured.

Once the bale/bales have been sufficiently reduced, the lower part 17 is put into operation as well by activating the coupling 28 that is schematically indicated in Fig. 3, which coupling connects the lower part 17 to the shaft end 20 that also drives the vertical shaft of the upper part 16. When both parts 16,17 of the mixing screw 8 are driven, the entire contents of the container 1 are mixed within a short period of time. It will be understood that also feeds that are separately added may be mixed with the feed material from the bales in that case. When the two parts 16,17 of the mixing screw 8 are coupled together with a view to further reducing and mixing the feed material, possibly also with other feeds that are separately added, the mixing screw 7 can be engaged as well. The mixing screw 7 may also be engaged when only the upper part 16 of the mixing screw 8 is being driven .

Fig. 4 is a top plan view corresponding to Fig. 2 of an embodiment of the apparatus according to the invention, which is configured in substantially the same manner as the embodiment according to Figs. 1-3. In this embodiment, the coupling arm 25 is configured as an articulated arm compris- ing two parts 25a and 25b, which are pivotally interconnected at 25c. The two arm parts 25a, 25b are held in the illustrated position by a spring 25d (shown very schematically) . It will be understood that the spring 25d may be configured in any desired manner and that said spring may be accommodated in the interior of the articulated arm 25. The _^ articulated arm 25 can pivot against the action of the spring 25d during rotation and/or pivoting of the upper part 16, so that the mixing element will be capable of coping with shock loads caused by large chunks of feed and that it cannot get jammed.

Rs noted above, the lower part 17 comprises one or more blades 18, which are shown in Figs. 1 and 2 and which are partially shown yet in Fig. 3. Said blades 18 are mounted on disc segments 29, which are rotatable about the shaft end 20 via bearings 30. The disc segments 29 support a hydrauli- cally actuated disc brake or clamp 31, which can engage a ring-shaped disc 32. The disc 32 is supported by a carrier 33, which is mounted on the shaft end 20. The carrier 33 also supports the spherical part 22. It is noted that the coupling 28 described herein may also have a different configuration.

Although it is preferable to configure the mixing screw 8 in the above-described manner with an upper part 16 and a lower part 17, which upper part 16 is pivotable, it is also possible to use an embodiment of the apparatus according to the invention in which the mixing screw consists of two parts, the upper part of which is not pivotable. Furthermore it is possible to use a one-part pivotable mixing screw. In Fig. 5 a part of a mixing screw 34 is shown by way of example in a similar manner as in figure 3, which mixing screw consists of an upper part 35 and a lower part 36. The upper part 35 is not pivotable in this case. The upper part 35 is driven via the right-angled gearbox 14, which is shown schematically in Fig. 5. The right-angled gearbox 14 has a vertical shaft 37, which drives the upper part 35 provided with the helical mixing blade 15. On said shaft 37, the disc 29 is rotatably mounted in bearings 30, which disc 29 carries one or both blades 18 in the above-described manner. In this embodiment, the disc 29 supports the ring-shaped disc 32, on which the disc brake or clamp 31 engages. Said disc brake 31 is mounted on the carrier 33 that forms part of the upper part 35.

Fig. 6 schematically shows a variant of the upper part 16 of the mixing screw 8, in which a mixing wheel 38 supporting a plurality of projecting loosening element^ 29 is mounted on the helical mixing blade 15. Said loosening elements may be configured as pins or knives, for example. Fig. 7 shows a view of the part of the mixing blade 15 on which the mixing wheel 38 is mounted. As the figure shows, the mixing wheel is rotatably mounted within a stripper disc 40, which is likewise rotatably mounted on the mixing blade 15. The shaft 41 of the stripper disc 40 is spaced further from the circumference of the mixing screw 8 than the shaft 42 of the mixing wheel 38. The stripper disc 40 has a circumferential edge 43 provided with passages through which the loosening elements.39 extend. When the mixing screw 8 is rotatably driven, the loosening elements 39 project into the material of the bales, thereby causing the mixing wheel 38 to rotate. This contributes towards reducing the bales. The loosening elements 39 are. pulled inwards relative to the circumferential edge 43 during rotation of the mixing wheel and the disc 40, as a result of which any material that may adhere to the loosening elements 39 is removed therefrom. In Fig. 7 it is indicated that the mixing blade 15 has an adapted outer edge at the location of the mixing wheel 38, so that the loosening elements project outside the mixing blade 15 along a large part of their rotational path. It is also possible to maintain the usual helical shape of the mix- ing blade 15, however.

Figs. 8 and 9 are very schematic views of a variant of a mixing screw 8 provided with a mixing blade 15, in which a mixing wheel 38 provided with loosening elements 39 is used without the disc 40. Figs. 10 and 11 show a variant of the mixing screw

8, in which a mixing wheel 44 having a conical shape is used, whilst the loosening elements 39 lie in the conical plane of the mixing wheel 44. In the embodiment that is shown in Figs. 10 and 11, the shaft 45 of the mixing wheel AA is perpendicular to the mixing blade 15. Figs. 12 and 13 show a variant of the conical mixing wheel 44, in which the shaft 45 is tilted, as is apparent in particular from Fig. 13. It is noted that although only one mixing wheel is used in the embodiments described herein, it is also possjL- ble, if desired, to use two or more mixing wheels distributed over the mixing blade 15 of the mixing screw.

The top plan view of Figs. 2 and 4 shows that the apparatus described herein is provided, in a manner that is known per se, with an outlet opening 46 that can be closed by- means of a slide (not shown) . The outlet opening 46 connects to a cross conveyor 47, via which the mixed feed can be delivered to the left-hand side or the right-hand side of the apparatus.

Fig. 14 is a side view of a mixing element 48 that can be used in an alternative embodiment of the apparatus according to the invention. The mixing element 48 comprises a lower part 49 and an upper part 50, the lower part 49 com- prising two blades 51 and the upper part 50 comprising a helical mixing blade 15. If desired, the lower part 49 may comprise only one blade 51. One of the blades 51 is shown in more detail in Figs. 15-17. In this embodiment, the blades 51 can be rendered inoperative by means of an actuating element 52 comprising a cylinder-piston assembly. Each blade 51 is rotatably connected to a carrier plate 54 near an end edge 53, being movable by means of the actuating element 52 between an operative position, which is shown in Figs. 14-16, and an inoperative position, which is shown in Fig. 17. In the operative position, the blade 51 slopes upwards, and in the inoperative position the blade 51 has a substantially flat orientation and is supported on the carrier plate 54. A chamber 55 is formed in the blade 51, in which chamber the actuating element 52 is accommodated. As Figs. 16 and 17 show, the actuating element 52 also comprises a rod 56, one end of which is rotatably connected to the carrier plate 54 at 57 and the other end 58 of which is rotatably connected to the cylinder-piston assembly. When the piston of the cylin- der-piston assembly is moved outwards, the end 58 of the rod 57 pushes the blade 51 from the inoperative position that is shown in Fig. 17 to the operative position that is shown in Fig. 16. The outer edge of the blade 51 , which extends upwards in the operative position, comprises an end portion_^ 59 that is hinged to the other part of the blade 51. The hinges are schematically indicated at 60. The hinges 60 comprise a stop 61 (schematically indicated} , which holds the end por- tion 59 in the position that is shown in Figsl 16. When the blade 51 moves towards the inoperative position that is shown in Fig. 17, the end portion 59 can lie substantially flat on the carrier plate 54.

When the blades 51 of the lower part 49 are in the operative position that is shown in Fig. 17, the lower part 49 of the mixing element 48 will have been rendered inoperative, so that only the upper part 50 will engage the bales or bales of feed in the container 1 for reducing the bales when the mixing element 48 is. being driven. This means that the lower part.49 need not lift the weight of the entire feed mass, so that a relatively low power level for driving the mixing element 48 will suffice.

It is noted that the upper part 50 of the mixing element 48 may be pivot-mounted in the same manner as the up- per part 16 of the mixing element 8.

Figs. 18 and 19 show a partially cutaway side view and a top plan view, respectively, of an alternative embodiment of the apparatus according to the invention. This embodiment is configured in substantially the same manner as the apparatus according to Figs. 1 and 2, so that corresponding parts will not be described again. In this case mixing elements 62, 63 are used, with the mixing element 63 comprising an upper part 64 and a lower part 65. The mixing element 63 may be configured in the same manner as the mixing ele- ments 8, 34 or 48 as described above.

The apparatus according to Figs. 18 and 19 is provided with a guide member 66 in the form of a fork, wherein teeth 67 of the guide member 66 are connected to a bearing rod 68, which is rotatably mounted in bearings 69. The bearing rod 68 is also capable of vertical reciprocating movement to a certain degree in the bearings 69. It is preferable in this connection if a drawback spring is provided, which presses the bearing rod 68 downwards.

The guide member 66 is movable between an .inoperative position, which is illustrated in a broken line in Fig. 19, in which the teeth 67 abut against the vertical wall 3 of the container 1, and an operative position, in which the teeth 67 extend towards the mixing element 63. The guide member 66 can be moved between the operative position and the inoperative position by means of a cylinder-piston assembly 17. Although the bearing rod 68 and the bearings 69 are visible in the drawing, a screening plate will be provided in practice, so that the presence of the bearing rod 68 and the bearings 69 does not constitute an impediment for the feed in the container 1.

In the embodiment that is shown in Figs. 18 and 19, the teeth 67 of the guide member 66 extend substantially ra- dially relative to the shaft of the mixing element 63 in the operative position. Alternatively, the teeth 67 of the guide member of 66 may be directed at a point below the shaft of the mixing element 63, so that the feed material will be pressed more gradually in the direction of the shaft of the mixing element by the rotation of the mixing element. It is also possible, of course, to mount the bearings 69 at another position on the vertical wall 3 of the container 1, for example above the longitudinal axis of the apparatus.

It is also possible with the apparatus according to Figs. 18 and 19 to move the guide member 66 gradually from the inoperative position to the operative position while the bale or bales is (are) being reduced, so that the feed material is guided further towards the mixing element 63 as the reduction of the bale/bales progresses. Figs. 18 and 19 schematically show a fork 71 whose teeth extend horizontally into the container 1 through the vertical wall 3. The fork 71 is pivotable between an operative position as shown in Fig. 18 and 19 and an inoperative position as illustrated in a broken line in Fig. 18. To that end the rods 72, which are on the one hand connected to the fork 71, are on the other hand connected to a rotatable rod 73. The rod 73 can be rotated by an actuating element 74, which is only partially shown in Fig. 18. When the fork 71 is in the operative position, the lower part 65 of the mixing element 63 will be at least partially inoperative because the teeth of the fork 71 extend at least partially above the lower part 65 and the fork 71 supports the bale / bales at least partially. It is noted that the number of teeth and the length of the teeth of the fork 71 shown in Figs. 18 and 19 are only given for the purpose of illustration. Different dimensions and a different number of teeth are possible. The teeth of the fork 71 may slope downwards from the vertical wall 3 of the container 1 in the direction of the mixing element 63, so that the bale/bales are guided in the direction of the mixing element.

In this embodiment with the fork 71 it is possible, if desired, to use a one-part mixing element instead of a two-part mixing element, because in the operative position the fork 71 functions as a means for rendering the lower part of the mixing element inoperative. It will be understood that the fork may also be used in the other embodiments of the apparatus according to the invention described herein. Figs. 20-22 schematically show a side view of a mixing element 75 that can be used in an alternative embodiment of the apparatus according to the invention. Like the mixing elements described in the foregoing, said mixing element 75 comprises a helical or spiral blade 76, whose diameter gradually decreases in upward direction. At the end located near the bottom, the blade 76 joins a blade portion 77, which is movable between an inoperative position as shown in Fig. 21 and an operative position as shown in Fig. 22. According to another possibility, however, an interruption is present between the blade 76 and the blade 77, and two blade portions may be present under the blade 76. As the top plan view of Fig. 21 shows, the blade portion 77 is retracted in the direction of a column 78 in the inoperative position, to which column 78 the blade 76 is attached. In this inoperative position, the blade portion 77 largely extends within the circumference of the higher remaining portion of the blade 76, so that the mixing element 75 has a significantly reduced diameter. This means that the lower part of the mixing element 75 is rendered substantially inoperative in the -~ retracted position of the blade portion 77. As a result, said blade portion 77 is hardly loaded by lifting the entire weight of the feed mass, so that a low power level will suf- fice for driving the mixing element 75.

In the operative position that is shown in Fig. 22, the blade portion 77 has been pivoted completely outwards, so that the diameter of the mixing element 75 is much larger than in the inoperative position that is shown in Fig. 21. As a result, this blade portion 77, too, will be operative when the mixing element 75 is driven. The blade portion 77 is moved to this operative position once the feed mass has been sufficiently reduced.

As shown in a broken line in Figs. 21 and 22, the blade portion 77 is supported on a support arm 79, which is shown in side view in Fig. 20. The support arm 79 is attached to a sleeve 80, which is rotatable about a shaft 80a. Said shaft 80a is connected by arms 81a to a cylindrical portion 81, which is coaxial with the column 78, being integral therewith via the blade 76.

Said cylindrical portion 81 furthermore carries a cylinder-piston assembly 82, whose cylinder housing is ro- tatably connected to the portion 81 and whose piston rod is rotatably connected to the support arm 79. The blade portion 77 can be moved between the inoperative position and the operative position by means of said cylinder-piston assembly 82.

With the mixing element 75, the pitch of the blade 76 near the bottom end 83 is smaller than the pitch of the higher portion of the blade 76 that is indicated at 84. In this way an improved mixing action of the mixing element 75 is obtained. Such a variable pitch is also possible with the other mixing elements described herein, of course . Figs. 23A and 23B show a part of a mixing element 85 which comprises a lower blade 86 (only partially shown) , and an upper blade 87. The lower blade 86 carries a rotatably suspended knife 88 at the end thereof, which knife is held in the operative position as shown by means of a spring 89. When the pressure on the knife 88 becomes too large, the knifs 88 can pivot in the direction of the shaft of the mixing element 85 against the action of the spring 89. Rotary knives 88 may also be provided at other positions along the circumference of the blade 86, of course.

The pitch of the lower blade 86 is such that said blade 86 transports the feed in upward direction during operation, whilst the pitch of the upper blade 87 is such that said blade transports the feed in downward direction. This leads to an improved mixing action of the mixing element 85. Furthermore, the cutting action of the knife 88 is improved. Such an upper blade portion transporting in downward direction may also be used with the other mixing elements described herein. It is noted that the leading (in use) end edge 90 of the upper blade 87 may be configured as a cutting edge with a view to improving the action of the mixing element. In the illustrated embodiment, said end edge 90 is rounded. As a result, feed is prevented from folding around the end edge 90 and the feed is guided under the blade in a more efficient manner.

Fig. 24 is a very schematic top plan view of a mixing element 91, which mixing element consists of a column 92, to which a helically extending blade 93 is attached. Said blade 93 functions as a carrier for a number of partially overlapping discs 94, which are mounted on the blade 93, being rotatable about a shaft 95. As a result, the friction that occurs between the mixing element 91 and the feed mixture in the mixing container is significantly reduced. It is noted that although rotary discs 94 are only provided on part of the blade 93 in Fig. 24, it is also possible to use a smaller or a larger number of such discs, of course. Further- more it is possible to use a helically bent rod or beam as a carrier instead of the blade 93.

From the foregoing it will be understood that the invention provides an apparatus for processing feed wherein a 5 relatively low power level is needed for driving the mixing element. In the above-described apparatus comprising two_^^nix- ing elements in the form of mixing screws, only the upper part of the two-part mixing screw is put into operation at the start of the mixing process, for example, and after some

10 time, when the bale or bales have been sufficiently reduced, the lower part is put into operation as well. Subsequently, after mixing with one mixing element has taken place for some time, the ^■ second mixing element may be put into operation, if desired. If both mixing elements of the apparatus are two-

15 part elements, the two parts of the second mixing element may be put into operation one after the other as well, whilst it is also possible to put the two upper parts and the two lower parts successively into operation. According to the invention, the activation of the various mixing elements and the

20. upper and lower parts can- be carried out by an automatic control unit in dependence on the load on the drive unit. If the load on the drive unit falls below a predetermined value after the upper part has been put into operation, the lower part is put into operation, for example, and if subsequently

25 the load falls below a predetermined value again, the second mixing element may be activated. With apparatuses comprising three or more mixing elements it is of course possible in a similar manner to put each of the mixing elements into operation, whether or not partially, in dependence on the load on 0 the drive unit.

It is noted that it is also possible to use other types of mixing elements instead of the mixing screws described herein, for example mixing elements having projecting mixing arms or the like. 5 Accordingly, the invention is not restricted to the embodiments as described in the foregoing, which can be varied in several ways without departing from the scope of the invention as defined in the claims .

Claims

CIAIMS

1.An apparatus for processing feed for cattle, comprising a container having a bottom and an upstanding wall and at least one mixing element, which is rotatably mounted in the container about a shaft that extends upwards from-the bottom thereof, and which can be coupled to a drive unit, characterized in that the mixing element comprises an upper part and a lower part, while means are provided for rendering the lower part of the mixing element inoperative.

2. An apparatus according to claim 1, wherein the upper part and the lower part can each be coupled to the drive unit.

3.An apparatus according to claim 2, wherein the lower part of the mixing element can be coupled to the upper part so as to be driven by the drive unit.

4. An apparatus according to claim 1, wherein the lower part of the mixing element comprises one or two blades, each blade being movable between an operative position, in which the blade extends upwards, and an inoperative position, in which the blade extends substantially horizontally.

5. An apparatus according to claim 4, wherein each blade is rotatably connected to a carrier plate near an end edge, wherein an actuating element is provided between the blade and the carrier plate for moving the blade between the operative position and the inoperative position, wherein a chamber is preferably formed in the blade, in which chamber the actuating element is accommodated, wherein preferably an end portion is pivotally connected to the blade at the end of the blade that takes up a high position in the operative position.

6. An apparatus according to claim 1, 2 or 3, wherein the mixing element is configured as a mixing screw provided with a helically extending blade comprising a blade portion that is movable between an inoperative position, in which the blade portion is retracted and is at least par- tially positioned within the circumference of the blade positioned thereabove, and an operative position, in which the blade portion projects further beyond the circumference of the higher helical blade.

7. An apparatus according to claim 6, wherein the movable blade portion is supported on a supporting arm, which is pin-pivoted to the mixing screw.

8. An apparatus according to any one of the preceding claims, wherein the upwardly extending shaft of the mixing element is pivot-mounted in the container.

9. An apparatus according to claim 8, wherein an actuating unit is provided, which actuating unit is capable of moving the upwardly extending shaft of the mixing element along a pivoting path through the container.

10. An apparatus according to claim 9, wherein the actuating unit comprises a coupling arm and a driving ele- ment, said coupling arm being mounted between the upper end of the vertical shaft and the wall of the container and said driving element being mounted between the coupling arm and the wall of the container.

11. An apparatus according to claim 10, wherein said coupling arm is configured as an articulated arm, the two parts of which can pivot relative to each other against the action of a spring, in such a manner that the upwardly extending shaft of the mixing element makes a pivoting movement in a direction away from the container wall.

12. An apparatus according to any one of the claims 8-11, wherein the upwardly extending shaft is coupled to a driven shaft via a universal joint, which joint is accommodated in a closed housing comprising two spherical members that fit together, one spherical member being con- nected to the upwardly extending shaft and the other spherical member being connected to the driven shaft .

13. An apparatus according to any one of the claims 8-12, wherein the pivotable upwardly extending shaft is the vertical shaft of the upper part of the mixing ele- ment.

14. An apparatus according to any one of the claims 9-13, wherein the pivoting path of the upwardly extending shaft extends in such a manner that the dimension of the passage between the wall of the container and the mixing element varies .

15. An apparatus according to claim 14, wherein the pivoting path extends at least substantially in the lon- gitudinal direction of the container.

16. An apparatus for processing feed, which apparatus comprises a container and at least one mixing element, which is rotatably mounted about an upwardly extending shaft in the container and which can be coupled to a drive unit, characterized in that the upwardly extending shaft of the mixing element is pivot-mounted in the container.

17. An apparatus according to any one of the preceding claims, wherein at least two mixing elements are provided in the container, which mixing elements can be sepa- rately coupled to the drive unit, wherein at least one of said mixing elements comprises a pivotable upwardly extending shaft and/or an upper part and a lower part, which can each be coupled to the drive unit .

18. An apparatus according to any one of the pre- ceding claims, wherein a guide member is provided in the container, which guide member is movable between an operative position, in which the guide member extends from the upwardly extending wall to a mixing element, and an inoperative position, in which the guide member abuts against the upstanding wall of the container.

19. An apparatus according to claim 18, wherein the guide member, in the operative position thereof, extends gradually from the upstanding wall towards the mixing element, seen in the direction of rotation of the mixing element.

20. An apparatus according to claim 18 or 19, wherein the guide member is configured as a guide fork.

21. An apparatus according to any one of the preceding claims, wherein the means for rendering the lower part of the mixing element inoperative comprise a fork, which fork is movable between an operative position, in which the teeth of the fork extend substantially horizontally in the container in the direction of the mixing element, and an inoperative position, in which the teeth of the fork are positioned outside the space in the container, wherein the teeth of the fork extend at least partially above the lower part of the mixing element in an operative position and re- lease the lower part in the inoperative position.

22. An apparatus according to any one of the preceding claims, wherein the mixing element is configured as a mixing screw provided with a helically extending blade comprising a lower and an upper blade portion, wherein the lower blade portion transports in upward direction and the upper blade portion transports in downward direction during operation.

23. A mixing element^ for an apparatus according to any one of the preceding claims, characterized in that the mixing element comprises an upper apart and a lower part, whilst means are provided for rendering the lower part of the mixing element inoperative.

24. A mixing element according to claim 23, wherein the upper part and the lower part are rotatable rela- tive to each other about a common axis.

25. A mixing element according to claim 23, wherein the lower part of the mixing element comprises one or two blades, each blade being movable between an operative position, in which the blade extends upwards, and an inoperative position, in which the blade extends substantially horizontally.

26. A mixing element according to claim 23, wherein the mixing element is configured as a mixing screw provided with a helically extending blade comprising a blade portion that is movable between an operative position, in which the blade portion is operatively incorporated in the helical, and an inoperative position, in which the blade portion is retracted, being positioned at least partially within the circumference of the blade positioned thereabove.

27. A mixing element according to any one of the claims 23-26, wherein the shaft of the upper part is pivo- table relative to the shaft of the lower part.

28. A method for processing feed for cattle, wherein one or more bales of feed are deposited into a container comprising a bottom and a vertical wall, and a mixing element mounted in the container is rotatably driven for re- ducing and mixing the material from the bale or bales, characterized in that the mixing element comprises an upger part and a lower part, wherein in a first processing step the bale/bales is/are reduced by means of one part of the mixing element and wherein in a second processing step the bale/bales is/are reduced by both parts of the mixing element .

29. A method according to claim 28, wherein two or more mixing elements are mounted in the container, wherein, in one or more next processing steps, a second or a next mix- ing element is put into operation for reducing the bale/bales.

30. A method according to claim 28 or 29, wherein the transition from the first processing step to each next processing step takes place in dependence of the load on a drive unit that drives the mixing element (s).