Patent Publication Number: US-2021176913-A1

Title: Metering unit for granular material

Description:
The present invention relates to a metering unit for granular material according to the preamble of claim  1  and to an agricultural distributing machine according to the preamble of claim  3 . 
     A distributing machine for distributing seed, fertilizer or the like is known from reference EP 2 832 202 B1. This distributing machine comprises a storage container with a plurality of metering units for granular material, a metering unit being configured for conveying the granular material in adjustable quantities. For this purpose, the respective metering unit comprises a metering housing. The metering housing has arranged therein a rotatably supported metering wheel. In operation, the metering wheel is caused to rotate by a drive, so that granular material is conveyed by means of the metering wheel. In addition, the metering unit comprises a shut-off valve that is adapted to be displaced to various positions. The shut-off valve can thus be displaced to various positions, thus opening a desired opening cross-section through which granular material can flow into the metering housing. Hence, the shut-off valve has to be opened for operation so that granular material can flow-in continuously. If operation does not take place, the shut-off valve has to be displaced to such an extent that the opening cross-section is closed, so as to prevent undesired discharge of the granular material from the storage container to the metering wheel. 
     This metering unit comprises devices for rotatably supporting the metering wheel. When the metering unit is in operation, a differential torque occurs between the force input and force output side of the metering wheel, which must be absorbed and dissipated in a suitable manner. In this metering unit, a form-fit connection by means of a groove is provided for this purpose at the devices which are used for the purpose of rotatably supporting and which are difficult to access in any case. This complicated structural design makes initial assembly and maintenance more difficult. 
     Hence, the task underlying the present invention is to provide of a metering unit, which is used for an agricultural distributing machine and which has a simplified bearing for the metering wheel. 
     According to the present invention this task is solved in that, for rotatably supporting the metering wheel, the metering unit includes a bearing housing, that the bearing housing comprises a locked position, at which the bearing housing is secured in position on the metering housing in an axial direction, and an unlocked position, at which the bearing housing is removable from the metering housing, that the bearing housing is adapted to be rotated between the locked position and the unlocked position, that the metering housing includes a metering cover which is movable to various positions, that the metering cover comprises a first position protecting the metering wheel and a second position uncovering the metering wheel, that the metering cover includes an extension, preferably a nose-piece-like extension, that, at the first position of the metering cover, the extension defines an abutment for the bearing housing and is adapted to block a rotary movement of the bearing housing from the locked position to the unlocked position. 
     As a result of this measure, the metering device is provided with a particularly easily accessible bearing. In addition, the groove for establishing a form-fit connection is no longer necessary, since the bearing housing rests on the metering cover by means of the abutment. Differential torques occurring at the bearing housing during operation are absorbed in a simple manner by the bearing housing and dissipated to the metering cover. Hence, the metering unit according to the present invention is characterized by a particularly simple and safe structural design. 
     In addition, an advantageous further development of the metering unit according to the present invention is that the metering cover is arranged on the metering housing by means of a pivot joint having a pivot axis, that the metering cover is movable between the first and the second position by means of the pivot joint. An advantage achieved in this connection is that the metering cover is undetachably arranged on the metering housing. This means that, even when work is carried out on the interior of the metering housing, the metering cover will be fixed to the metering housing and need not be retained with special care nor can it be damaged by falling down. 
     According to another advantageous further development of the present invention, the metering cover includes a lug on the side facing the shut-off valve, the metering cover having assigned thereto a locking device, by means of which the metering cover is secured at the first position, and the locking device comprises a locking element, which is adapted to be pushed away and which is configured for establishing a releasable, form-fit connection with the lug of the metering cover at the first position of the metering cover, the shut-off valve being arranged behind the locking device in the push-away direction of the locking element and having a reception unit for the locking element, the shut-off valve being, by means of the reception unit, configured for allowing and/or blocking the pushing away of the locking element. 
     As a result of this measure, the metering unit is configured with two successive safety steps, so that the protection for the user during handling is increased in an excellent manner. The first safety step is defined by the locking device, without an actuation of which the interior of the metering housing is not accessible to the user. This locking device is additionally secured through the position of the shut-off valve, which defines the second safety step. 
     The shut-off valve with its reception unit for the locking element is arranged behind the locking device such that the locking element can be displaced into the reception unit, in particular by pushing it away. The reception unit on the shut-off valve is arranged such that the locking element can only be displaced into the reception unit, if the shut-off valve is located at its closed position. As soon as the shut-off valve has been displaced to an at least partially open position, the reception unit is no longer in alignment with the locking element so that the displaceability of the locking element is blocked. This means that, during operation of the metering unit, the interior of the metering housing is no longer accessible to the user, since an actuation of the locking device is already prevented by the open position of the shut-off valve and the metering cover is thus secured at its first position protecting the metering wheel. 
     It follows that, for opening the metering housing, it will be necessary to displace the shut-off valve to the closed position, so as to allow the displaceability of the locking element. The metering unit is typically not in operation when the shut-off valve is closed, so that it will be safe for the user to open the metering cover without coming into contact with the driven metering wheel. 
     According to an advantageous further development of the present invention, the metering housing comprises a first stop for limiting the rotary movement of the bearing housing from the unlocked position to the locked position, the extension defining, at the first position of the metering cover, a second stop, which is preferably located opposite the first stop, and the bearing housing being adapted to be secured in position on the metering housing in a rotationally fixed manner between the first stop and the second stop. It follows that the bearing housing is not only secured in position on the metering housing in an axial direction, but is also held between the first stop and the second stop at the locked position that is safe for operation. In an advantageous manner, the first stop serves here to limit the mounting movement of the bearing housing. 
     The task underlying the present invention is additionally solved by an agricultural distributing machine of the type referred to at the beginning, the agricultural distributing machine including at least one storage container for seed, fertilizer or the like, and the storage container having assigned thereto at least one metering unit, the metering unit being configured according to at least one of the preceding embodiments. 
    
    
     
       Further details of the present invention can be seen from the description of the examples and from the drawings. In the drawings 
         FIG. 1  shows, in a perspective view, an agricultural distributing machine trailed behind an agricultural tractor, 
         FIG. 2  shows, in a perspective view, a metering unit according to the present invention including a shut-off valve in a closed position, 
         FIG. 3  shows, in a perspective view, the metering unit, the shut-off valve being in an open position, 
         FIG. 4  shows, in a sectional view and detail view, the metering unit with a locking device, 
         FIG. 5  shows, in a sectional view and detail view, the metering unit with the locking device unlocked, 
         FIG. 6  shows, in a perspective view, the metering unit with a metering cover in an open position, 
         FIG. 7  shows, in a side view, the metering unit with a bearing housing, 
         FIG. 8  shows the metering unit in a side view, the bearing housing being at a removable position, and 
         FIG. 9  shows the metering unit in a side view. 
     
    
    
     An agricultural distributing machine configured as a precision air seeder  1  is shown in  FIG. 1 . The precision air seeder  1  is trailed behind an agricultural tractor  2 , so that the two machines can move together in operation over a field to be worked in the direction of travel F and distribute granular material, such as seed or fertilizer. The precision air seeder  1  comprises, at its rear end in the direction of travel F, a plurality of sowing units  3  arranged transversely to the direction of travel F. The sowing units  3  are fixed to the frame  1 A of the precision air seeder  1 , the frame  1 A being adapted to be folded or telescoped to the permissible overall width for road haulage. 
     Each of the sowing units  3  is fixed to the frame  1 A of the precision air seeder  1  by means of a respective mounting flange. In the upper area, the sowing units  3  have a first storage container  4 , primarily for seed, and two second storage containers  5 , primarily for granular material. In the lower area, which faces the ground, the sowing units  3  are provided with soil cultivation implements  6 . The soil cultivation implements  6  serve to open a seed furrow and to close it again after seed and granular material have been delivered thereinto. 
     For the delivery of seed from the first storage container  4 , the sowing units  3  each comprise a singling unit  7 . The singling unit  7  is connected to the first storage container  4  on the one hand and to the soil cultivation implements  6  on the other, and it is configured for delivering singled seed into the seed furrow. For conveying granular material in adjustable quantities, the sowing units  3  each comprise two metering units  8 . The respective metering units  8  are assigned to the second storage containers  5  and arranged at an outlet of the same. The granular material conveyed by the metering units  8  is also guided to the soil cultivation implements  6 , where it is worked into the soil. 
     A metering unit  8  according to the present invention is shown in a perspective view in  FIG. 2 . The metering unit  8  essentially comprises a metering housing  9 , a drivable metering wheel  10  arranged in the metering housing  9 , a metering cover  12  and a displaceable shut-off valve  11 , which is here closed in  FIG. 2 . The metering housing  9  can be arranged on a second storage container  5  via fastening hooks  13  on its rear side  8 R. On the rear side  8 R of the metering housing  9  there is an inlet, concealed here in  FIG. 2 , for granular material from the second storage container  5 . This inlet is covered by the shut-off valve  11  when the shut-off valve  11  is closed, so that no granular material can flow into the metering housing  9 . It follows that the shut-off valve  11  is shown in  FIG. 2  at its closed position. In order to allow a flow of granular material into the metering housing  9 , the shut-off valve  11  can be displaced, i.e. opened, as shown in  FIG. 3 , so that an opening cross-section of the inlet into the dosing housing  9  will be uncovered. 
     In order to allow a user to work on the inside of the metering housing  9 , the metering cover  12  can be moved between different positions by means of a pivot joint having a pivot axis  14 . In  FIG. 2 , the metering cover  12  is shown at a first position protecting the metering wheel  10 , i.e. the metering housing  9  is closed. At this first closed position, the metering cover  12  has assigned thereto a locking device  15 , which prevents the metering cover  12  from being moved unwantedly into a second position uncovering the metering wheel, as shown in  FIG. 6 . 
     The locking device  15  includes a locking element  16  that is adapted to be pushed away. The locking element  16  is configured to establish a releasable, form-fit connection according to the principle of a snap connection with the metering cover  12  and to thus secure the latter at its first position protecting the metering wheel  10 . In order to release this form-fit connection and thus open the metering housing  9 , the locking element  16  is adapted to be pushed away in the direction of the rear side  8 R. For this purpose, the metering unit  8  comprises means, configured as a tool  17  with a corresponding insertion aid  18  arranged on the metering cover  12 , for applying a push-away force. The insertion aid  18  defines a linear guide for the tool  17  in the actuation direction of the locking element  16 , thus facilitating the application of the displacement force. In addition, the insertion aid  18  is arranged so close in front of the locking element  16  that the locking element  16  cannot be actuated by hand. 
     In  FIG. 4 , the locking device  15  is shown in a detail view and sectional view. The locking element  16  is in contact with a lug  12 A of the metering cover  12 , thus forming the form-fit connection. In the position shown, the lug  12 A is lockingly engaged under the locking element  16 . The shut-off valve  11 , shown here in  FIG. 4  at the closed position, is arranged in the direction of the rear side  8 R behind the locking element  16 . The shut-off valve  11  comprises a reception unit used for the locking element  16  and configured as a recess  19 . If, making use of the tool  17 , the push-in force is now applied to the locking element  16  so as to release the locking device  15 , the locking element  16  will enter the recess  19  of the shut-off valve  11  under elastic deformation, as shown in  FIG. 5 . The form-fit connection between the locking element  16  and the lug  12 A of the metering cover  12  is thus released and the metering cover  12  can be pivoted about the pivot axis  14  into its second position uncovering the metering wheel  10 , as shown in  FIG. 6 . A prerequisite for allowing the locking element  16  to be pushed away into the recess  19  on the shut-off valve  11  is that the shut-off valve  11  is at its closed position. 
       FIG. 3  shows the shut-off valve  11  at its open position. At this position, the recess  19  is not located in the direction of the rear side  8 R behind the locking element  16 . If the user applied the push-away force to the locking element  16  by means of the tool  17  at this open position of the shut-off valve  11 , it would not be possible to push the locking element  16  away under elastic deformation and, consequently, the locking device  15  could not be released. It follows that, on the basis of the recess  19 , the shut-off valve  11  is configured to block the pushing away of the locking element  16  in its open position or to allow it in its closed position, as shown e.g. in  FIGS. 4 and 5 . The arrangement of the recess  19  on the shut-off valve  11  necessitates that the shut-off valve  11  must be closed so as to allow the locking element  15  to be released. Otherwise, the locking element  16  cannot be received in the recess  19  and hits against the shut-off valve  11  without releasing the lug  12 A. 
     It follows that, for opening the metering unit  8 , the user first has to close the shut-off valve  11 . Then, with the aid of the tool  17 , the push-in force can be applied to the locking element  16 . For this purpose, the tool  17  has to be inserted into the insertion aid  18  and pushed in the direction of the locking element  16 . As a result, the locking element  16  is pushed-in and the form-fit connection between the locking element  16  and the lug  12 A on the metering cover  12  is released, so that the metering cover  12  can finally be moved. For moving the metering cover  12 , the lug  12 A on the metering cover  12  is pivoted out of the form-fit connection. In the course of this process, the metering cover  12  pivots down about the pivot axis  14  into its second position uncovering the metering wheel  10 . 
       FIG. 6  shows the metering unit  8  in a perspective view with the metering cover  12  open. In the interior of the metering housing  9 , the metering wheel  10  can be seen. For rotatably supporting the metering wheel  10 , the metering unit  8  includes a removable bearing housing  20  with an approximately round cross-section. The bearing housing  20  comprises suitable means for supporting the metering wheel  10  and is insertable into a semicircular reception unit  21  on the metering housing  9 , as shown in a side view in  FIG. 7 . In order to releasably secure the bearing housing  20  in position on the metering housing  9 , the bearing housing  20  includes a groove-like recess  20 A on its circumference. This groove-like recess  20 A forms a slot and is thus adapted to engage behind a quarter-circular finger-shaped formation  21 A on the reception unit  21 . 
     The approximately octant-shaped formation  21 A on the reception unit  21  can be seen in  FIG. 8 , in which the bearing housing  20  is shown in an unlocked position allowing removal from the metering housing  9 . The bearing housing  20  can here be removed because the recess  20 A is not in engagement with the formation  21 A. The formation  21 A forms an undercut, so that, when the recess  20 A engages behind the formation  21 A, the bearing housing  20  is at a locked position fixed in an axial direction and at least partially in a horizontal direction. This locked position of the bearing housing  20  is shown in  FIG. 7 , where, in contrast to the unlocked position shown in  FIG. 8 , the recess  20 A engages behind the formation  21 A. 
     For inserting the bearing housing  20  into the reception unit  21  and for securing it thus in position on the metering housing  9 , i.e. for moving the bearing housing  20  from the unlocked position to the locked position, the bearing housing  20  has to be inserted into the reception unit  21 . This means that the bearing housing  20  is positioned in the reception unit  21  in such a way that the recess  20 A will be able to engage behind the formation  21 A. Such positioning of the bearing housing is exemplarily shown in  FIG. 8 . Rotating of the bearing housing  20  up to a first stop  23  of the bearing housing will then have the effect that the recess  20 A slides over the formation  21 A and receives the latter therein and thus engages behind it, as shown in  FIG. 7 . At this position of the bearing housing  20 , which is fixed to the metering housing  9 , the recess  20 A points at least approximately radially from the center axis of the bearing housing  20  in the direction of the base. In order to release the bearing housing  20  again, it will be necessary to rotate the bearing housing  20  in the reverse direction. This rotation in the reverse direction is blocked at the first position of the metering cover  12 . 
     The metering cover  12  has a nose-piece-like extension  22 , which, at the first position of the metering cover  12 , defines an abutment for the bearing housing  20 , as shown in  FIG. 9 . This ensures that the bearing housing  20  will not rotatably disengage unnoticed and unintentionally. In addition, the extension  22  thus forms a torque support for the bearing housing  20 . Torques absorbed by the bearing housing  20  during operation will be transmitted via the extension  22  to the metering cover  12  and from there they will be dissipated via the metering housing  9  to surrounding structures. At the first position of the metering cover  12 , the extension  22  additionally defines a second stop for the bearing housing  20  opposite the first stop  23 , so that the bearing housing  20  is secured in position on the metering housing in a rotationally fixed manner between the first stop  23  and the extension  22 . If the metering cover  12  is open, as shown in  FIG. 8 , the extension  22  does not define an abutment for the bearing housing  20 , so that a rotation of the bearing housing  20  in a direction opposite to the direction in which the first stop  23  is located will be possible. 
     LIST OF REFERENCE NUMERALS 
     
         
           1  precision air seeder 
           1 A frame 
           2  agricultural tractor 
         F direction of travel 
           3  sowing unit 
           4  first storage container 
           5  second storage container 
           6  soil cultivation implements 
           7  singling unit 
           8  metering unit 
           8 R rear side 
           9  metering housing 
           10  metering wheel 
           11  shut-off valve  11   
           12  metering cover 
           12 A lug 
           13  fastening hooks 
           13  pivot axis 
           14  locking device 
           15  locking element 
           17  tool 
           18  insertion aid 
           19  recess 
           20  bearing housing 
           20 A recess 
           21  reception unit 
           21 A formation 
           22  extension 
           23  first stop