Disc spreader with a discharge chute

Abstract

A disc spreader for distributing material, comprising a storage container (7) for receiving the material with at least one discharge opening (12), at least one metering element downstream of the discharge opening (12) of the storage container (7) with a metering opening (15), and at least one distributor disc (3, 4) arranged below the metering opening (15) and rotatable about an axis of rotation, wherein a discharge chute (10, 11) extends downwards from the metering opening (15) towards the distributor disc (3, 4), which surrounds at least a circumferential section of the metering opening (15), characterized in that the discharge chute (10, 11) extends substantially completely around the metering opening (15) at its free end facing the distributor disc (3, 4), wherein the discharge chute (10, 11) extends at least has a passage (26).

Description

[0001] The invention relates to a disc spreader for distributing material, with a reservoir for receiving the material to be distributed, having at least one outlet opening, at least one metering element downstream of the outlet opening of the reservoir with a metering opening, and at least one distributor disc arranged below the metering opening and rotatable about an axis of rotation, wherein an outlet chute extends downwards from the metering opening towards the distributor disc, which surrounds at least a circumferential section of the metering opening.

[0002] Disc or centrifugal spreaders are agricultural machines used to apply powdery or particulate materials, such as fertilizers or seeds, in a variety of designs. Examples include trailed, self-propelled versions and those mounted on the three-point linkage of a tractor. They comprise a hopper for the material to be applied, typically featuring one or two discharge openings at its base. Each discharge opening is equipped with a metering device, the metering orifice of which is aligned with at least a portion of the discharge opening. This device dispenses the desired quantity—or more precisely, the desired mass flow—of the material from the hopper. The metering device, usually positioned below the discharge opening, is operated either manually or, more specifically, by actuators.The metering unit can be opened and closed using actuators, servo motors, or similar devices to adjust the mass flow rate according to the desired quantity of material to be spread per unit area, the desired distribution width on the ground, the driving speed, and the physical properties of the material, such as its flowability. Below the metering opening of the metering unit is the distribution disc, usually equipped with throwing vanes or paddles, which distributes the material across the desired working width. This disc rotates around a typically vertical axis, either by connecting a drive train to the power take-off (PTO) of a tractor or by its own drive, such as a hydraulic motor, an electric motor, or similar device.

[0003] Modern disc spreaders are also equipped with a device for adjusting the point at which the material is applied to the spreading disc. This point can be adjusted radially (particularly to increase / decrease the spreading pattern) and / or circumferentially (particularly to rotate the spreading pattern around the axis of rotation of the spreading element). The device for adjusting the point of application comprises either one or more handles for manual adjustment of the point of application or one or more actuators, which can also be used, for example, to...These components may include actuators, servomotors, or similar devices, and are designed to move the metering opening of the metering unit back and forth relative to the distribution disc—and in special cases, also relative to the discharge opening, which is generally stationary with respect to the container. This back-and-forth movement, as indicated above, can be translational and / or rotational. In automatic machines, the control or regulation of the actuator of the device for adjusting the application point, depending on the desired distribution width, is handled by a programmatically configured control and / or regulation unit of the disc spreader. This unit is typically operatively connected to at least one operating module, which may, for example, be located in the cab of a tractor. The same generally applies to the control or regulation of the...The metering unit is controlled according to the desired mass flow rate of the material to be applied. If the disc spreader does not have a device for adjusting the application point, the discharge opening from the hopper can also be identical to the metering opening of the metering unit.

[0004] Such a disc spreader for agricultural purposes is known, for example, from DE 10 2007 053 550 A1, wherein the disc spreader is designed in the form of a twin-disc spreader, the hopper of which has at least two discharge openings arranged at a later distance from each other. A metering element with a metering opening is arranged downstream of each discharge opening of the hopper, wherein a distributor disc rotatable about an axis of rotation is arranged below each metering opening.

[0005] In the case of winter service spreaders, the hopper primarily serves to hold grit and / or road salt, usually in granular form. The function of such a winter service spreader largely corresponds to that of an agricultural spreader described above. Winter service spreaders can also have several, or in particular two, spreading discs, or even just one, which are typically also equipped with throwing vanes.

[0006] Furthermore, twin-disc spreaders are known, for example, from DE 38 06 756 A1 or EP 0 380 040 B1, in which a discharge chute extends downwards from the metering opening of each metering element towards a respective distribution disc. This discharge chute surrounds the metering opening by a portion of its circumference and is open at the bottom, so that the mass flow of material set by the metering element falls through the discharge chute before it impacts the distribution disc below or its spreading vanes. While such a discharge chute can protect the falling material from external influences, such as wind, its purpose is also to reduce so-called impact losses and metering errors, which occur in disc spreaders of this type, especially with relatively large mass flows of material or at high driving speeds and / or working widths.Impact losses refer specifically to over-fertilization occurring in the central area of ​​the lateral distribution of material on the ground. This is due to the fact that those material particles not captured by the spreading disc's vanes are accelerated or deflected in random directions as the vanes enter the falling stream of material due to impact forces. In contrast, the so-called quantity effect, which cannot be eliminated by the usual practice of driving along two parallel tramlines in the field, arises from the varying material loads on the spreading disc's vanes at different mass flow rates.While with small mass flows individual particles of the spread material are accelerated outwards at high speed and therefore reach the end of the throwing blade earlier, i.e., are released earlier (more is scattered towards the center), with increasing mass flow of spread material the throwing blade “fills up”, so that the pile of spread material slides more slowly outwards along the throwing blade and is therefore released later (more is scattered outwards).

[0007] A disadvantage of known discharge chutes for disc spreaders is, in particular, that external influences cannot be completely eliminated and there is still a risk that the metered flow of material being deflected laterally and not captured by the throwing vanes of the distribution disc in the intended manner.

[0008] The invention is therefore based on the objective of further developing a disc spreader of the type mentioned at the outset in a simple and cost-effective manner in such a way that, while at least largely avoiding the aforementioned disadvantages, spreading errors resulting from a deflection of the metered mass flow of material hitting the distribution disc, which are accompanied by an unintentional shift of the application point, are minimized.

[0009] According to the invention, this problem is solved in a disc spreader of the type mentioned above by the fact that the discharge chute extends essentially completely around the metering opening at its free end facing the distributor disc, wherein the discharge chute has at least one passage in the area of ​​its end facing away from the distributor disc.

[0010] The inventive design of the discharge chute of the disc spreader represents a purely mechanical and, in terms of construction, very simple and cost-effective further development of known discharge chutes, which always extend only around a partial circumference of the discharge opening of the storage container and / or the metering opening of the metering element, in that, according to the invention, the discharge chute extends at its free (lower) end facing the distributor disc or away from the metering opening of the metering element (or the discharge opening of the storage container) essentially completely around the metering opening, so that a discharge chute is formed that is completely closed at its free (lower) end facing the distributor disc and external influences on the metered flow of material falling from the metering opening onto the distributor disc are practically excluded.Since, in such a "closed" discharge chute, a considerable suction effect can occur due to the rotating distribution disc, depending on the rotational speed, which in turn can lead to an uncontrolled lateral deflection of the distributed material flow that should be avoided, the invention further provides at least one passage in a circumferential wall of the discharge chute for pressure equalization. This passage is arranged in the area of ​​the (upper) end of the discharge chute facing away from the distribution disc and towards the metering opening of the metering device (or the discharge opening), where the metered mass flow of distributed material falls directly out of the discharge opening or the metering opening without the risk of lateral deflection and a resulting shift in the point of application of the distributed material onto the distribution disc, as occurs in the free fall of the mass flow of distributed material near the distribution disc or the metering opening.whose throwing vanes would be the case, which applies particularly – although not exclusively – when the distributor disc rotates at a high speed and thus causes a relatively large suction effect. Consequently, incorrect dosing due to deviations of the result of a calibration test (with the distributor disc stationary) from the mass flow of distributed material metered during operation (with the distributor disc rotating) is avoided as a result of a suction effect – eliminated according to the invention – as are errors in the spreading pattern due to uncontrolled lateral deflections of the mass flow of distributed material striking the distributor disc or its throwing vanes, which falls through the discharge chute.

[0011] While the metering element can in principle be of any known design, it can preferably have a metering slide that interacts with the metering opening and is pivotable, in particular about a substantially vertical pivot axis, i.e., about a pivot axis arranged approximately parallel to the axis of rotation of the distributor disc, and which can be moved between a closed position in which it completely closes the metering opening and several open positions in which it partially and / or completely releases the metering opening, as is the case with most commercially available disc spreaders.

[0012] The outlet shaft according to the invention can, in principle, have only one or, in particular, a plurality of openings, such as two or three openings, in the area of ​​its end facing away from the distributor disc, which can be advantageous with regard to a higher mechanical stability of the outlet shaft and, in particular, with regard to a distribution of the pressure equalization to prevent a suction effect over a wider area.

[0013] In order to ensure reliable pressure equalization to prevent a suction effect while simultaneously providing reliable protection of the metered mass flow of distributed material from external influences, it has proven advantageous if the at least one passage extends around a circumferential section of the discharge shaft of at least approximately 30°, in particular at least approximately 45°, preferably at least 60°, such as at least approximately 75°, wherein the at least one passage, on the other hand, preferably extends around a circumferential section of the discharge shaft of at most approximately 180°, in particular at most approximately 150°, preferably at most approximately 120°, such as at most approximately 105°.

[0014] With regard to the total area of ​​the at least one or several culverts of the outlet shaft, it has been found that the total area of ​​the at least one culvert should be at least approximately 5%, in particular at least approximately 8%, of the total circumferential area of ​​the outlet shaft, whereby it is generally sufficient if the total area of ​​the at least one culvert is at most approximately 25%, in particular at most approximately 20%, of the total circumferential area of ​​the outlet shaft.

[0015] In order to provide the greatest possible protection for the mass flow of distributed material falling through the discharge chute, a preferred embodiment may provide that the discharge chute extends from directly below the metering device to directly above the distributor disc or its throwing vanes.

[0016] According to a further preferred embodiment, the discharge chute can be provided at its free (lower) end facing the distributor disc or away from the metering element with elastically flexible material strips, such as bristles, bristle bundles or the like, which extend at least around a circumferential section of the discharge chute in the direction of the distributor disc, in particular substantially around the entire circumference of the discharge chute.

[0017] In this case, the elastically compliant material strips preferably extend from the free (lower) end of the discharge chute facing the distributor disc or the metering element to just above the distributor disc or its throwing vanes. Such a design of the discharge chute, with elastically compliant material strips projecting downwards at its free end, particularly across its entire circumference, also allows the free ends of the material strips to reach the free end of the throwing vanes. The elastically compliant material strips of the discharge chute can advantageously be made of a plastic material, particularly a wear-resistant one.

[0018] The discharge chute can preferably be made of a plastic material, which is advantageously a thermoplastic polymer-based material. This facilitates recycling and thus increases environmental friendliness; furthermore, thermoplastic polymers offer the possibility of the discharge chute being designed as an injection-molded or 3D-printed part.

[0019] As already indicated, the disc spreader according to the invention can, in particular, be a twin-disc spreader whose hopper has at least two discharge openings arranged at a later distance from each other, wherein a metering element with a metering opening is arranged downstream of each discharge opening of the hopper, wherein a distributor disc rotatable about an axis of rotation is arranged below each metering opening, and wherein a discharge chute of the aforementioned type extends downwards from each metering opening in the direction of the respective distributor disc, which extends substantially completely around the metering opening at its free (lower) end facing the distributor disc or away from the metering element, wherein each discharge chute in the area of ​​its free (lower) end facing away from the respective distributor disc or away from the metering elementhas at least one passage at the (upper) end facing the metering device.

[0020] In such a twin-disc spreader, where the distribution discs typically rotate in opposite directions (the right-hand distribution disc, viewed in the direction of travel, rotates counterclockwise, and the left-hand distribution disc, viewed in the direction of travel, rotates clockwise), an advantageous embodiment may provide that the at least one opening is located in a circumferential region of the discharge chute, extending in a front and / or laterally outer circumferential section of the discharge chute (viewed in the direction of travel). This ensures that the at least one opening—in its rotational direction or...The circumferential direction of each distributor disc is considered - downstream of the point of impact of the metered mass flow of material onto the throwing blades of the distributor disc, so that for pressure surges caused by this, a reliable pressure equalization is given through the at least one passage, without a lateral deflection of the mass flow of material that would result in a displacement of the feed point.

[0021] Further features and advantages of the invention will become apparent from the following description of an exemplary embodiment with reference to the drawings. These show: Fig. 1 a schematic side view of an embodiment of a disc spreader in the form of a twin-disc spreader designed as an agricultural implement, which can be picked up by the three-point linkage of a tractor, viewed from the rear; Fig. 2 a schematic perspective view, shown in abbreviated form, of a disc spreader's hopper located on the underside of one of the two container parts according to Fig. 1 arranged bottom with a drain opening from above; Fig. 3 A schematic perspective detail view of the floor with the outlet opening corresponding to section A of the Fig. 2 including a stirrer arranged above it and a metering opening of a metering device arranged below it; Fig. 4 A schematic perspective detail view of one of the lower parts of the hopper of the disc spreader according to Fig. 1 with the outlet opening and the outlet shaft arranged below it and the distributor disc equipped with throwing wings, the metering device being omitted for illustrative purposes; Fig. 5 a schematic perspective detail view of the outlet shaft according to Fig. 4 viewed from a slightly oblique angle above; and Fig. 6 a schematic perspective detail view of the outlet shaft according to Fig. 4 and Fig. 5th view from a low angle.

[0022] In the Fig. Figure 1 shows an exemplary embodiment of a disc or centrifugal spreader according to the invention – in this case designed as a twin-disc spreader. The disc spreader has a frame 1 with a cross member 2, which, for example, in the case of a mechanical drive derived from the power take-off shaft of a tractor, the distribution discs 3, 4, which are equipped with spreading vanes or blades 5, 6, accommodate a transverse drive. In the case of a speed-controlled, hydraulic or electric drive, for example, the hydraulic or electric motors (not shown) assigned to each distribution disc 3, 4 are fixed to the cross member 2. In this way, the distribution discs 3, 4 are set in normally opposite directions of rotation during operation, whereby – viewed in the direction of travel F (see Figure 1) – the distribution discs 3, 4 rotate in the opposite direction. Fig. 2 and Fig. 3) - the right distributor disc rotates counterclockwise and the left distributor disc rotates clockwise when viewed from above, as seen in the direction of travel F. The disc spreader also includes a hopper 7, which in this case comprises two funnel-shaped hopper sections 8, 9, at the ends of which in the Fig. 1. The dosing opening is not visible from the bottom, and there is one dosing opening in each of the... Fig. 1. a metering element that is also not readily apparent. A discharge chute 10, 11 extends downwards from the metering opening of each metering element, extending from directly below the metering element to directly above the distribution disc 3, 4 or its throwing vanes 5, 6, and – as further described below with reference to the Fig. 4 to 6 explained in more detail - surrounds the entire circumference of the metering opening, so that the distributed material metered by means of a respective metering device falls through the downwardly open discharge shaft 10, 11 onto the respective distributor disc 3, 4 and is captured by its throwing vanes 5, 6.

[0023] Again Fig. 2 and in particular the Fig. As can be seen from Figure 3, each container section 8, 9, which tapers downwards in a substantially funnel-like manner, has a discharge opening 12 on its underside. In the present embodiment, this opening is approximately ring-shaped and eccentrically arranged in a base 13 that surrounds it. A metering element is arranged below each of the approximately ring-shaped bases 13 that define the discharge openings 12 of the storage container 7. Each metering element has a metering part 14, approximately plate-shaped, with a metering opening 15. This metering part can be moved back and forth, for example, by means of a device (not shown) for adjusting the point at which the material is applied to the distribution disc 3, 4. The free cross-section of the metering opening 15 can be controlled by means of a metering slide, which is also actuated, for example. The dosing slide, which is not visible in the drawing, is located below the dosing opening 15 on a vertical, i.e.h. arranged parallel to the axis of rotation of the distributor discs 3, 4, pivotally mounted on the pivot axis and between a closed position in which it completely closes the metering opening 15 (not shown), and the one in the . Fig. 2 and Fig. 3 recognizable opening positions in which it completely releases the metering opening 15, as well as any intermediate positions in which it partially releases the metering opening 15, as indicated by the arrow D in the Fig. 3 is indicated.

[0024] As from the Fig. 2 and Fig. As can be further seen in Figure 3, an agitator 16 is assigned to the outlet opening 12 of each container section 8, 9 of the storage container 7, arranged directly above each base 13, the vertical axis of rotation 17 of which coincides, for example, with that of the distribution discs 3, 4. The axis of rotation 17 of the agitator 16 can, for example, be mounted in the respective base 13 and be driven by a controllable drive, which is not shown in detail. The arrangement of the agitators 16 is chosen such that the space below the outlet opening 12 arranged in the respective base 13 on the one hand and the associated distribution disc 3, 4 on the other hand remains free, so that the distributed material can pass through the outlet shaft 10, 11 (see Figure 3). Fig. 1) can reach the distributor discs 3 and 4 without obstruction. In this way, the distributor discs 3 and 4 ( Fig. 1) The ends of their spreading vanes 5, 6 distribute the material into two separate spreading fans, which partially overlap, resulting in a shallow triangular spreading pattern. During subsequent passes, this produces a linear distribution. One spreading disc 3, 4 throws the material to the other side, extending to approximately half the working width, thus enabling border spreading. However, the present invention can, of course, also be implemented in any other design of a single- or twin-disc spreader for agricultural or winter service purposes.

[0025] Above each agitator 16, a retention device, such as a sieve, grate, grid or the like (not shown), can also be advantageously placed in the lower part of the container base 8, 9, which serves to retain foreign bodies, such as stones, clods of earth and the like, but also clumps of aggregate, so that these do not reach the metering device or the discharge shaft 10, 11 and cause blockages there.

[0026] As already indicated, below the outlet opening 12 formed in the base 13, the metering part 14 of a respective metering device, which is provided with the metering opening 15 and which interacts with the metering slide in a baffle-like manner, is approximately plate-shaped in the present embodiment and can be moved back and forth by means of the device for adjusting the feed point, e.g., by means of an actuator. This back-and-forth movement of the plate-shaped metering part 14 in the present embodiment is a rotational movement about the axis 17 – i.e., coaxial with the axis of rotation of the agitator 16 and coaxial with the axis of rotation of a respective distributor disk 3, 4 (see arrow P of the Fig. 3) in order to adjust the point of application of the dispensed material onto the distribution disc 3, 4 in the circumferential direction thereof. To shift the application points onto the distribution discs 3, 4, which are determined by the position of a respective metering opening 15 of a respective metering element 14, the metering elements 14 can therefore be rotated about their center of rotation 17 by means of a device for shifting the application point (not shown in detail). The device for shifting the application point can, for example, be such as that known from DE 10 2012 024 363 A1.

[0027] The Fig. 4 to 6 each represent an embodiment of the outlet shaft 10 of the Fig. 1 can be seen, whereby a detailed description of the other outlet shaft 11 with regard to its corresponding, but mirror-symmetrical design is omitted. As can be seen from the Fig. As can be seen from Figures 4 to 6, the outlet shaft 10 has a circumferential wall 20, which in the present case is essentially adapted to the circumference of the metering opening 15 and is aligned with the distributor disc 3 (see the Fig. 4) The outlet shaft 10 extends fully around the metering opening 15 at its end facing the base 13 with the outlet opening 12 and the metering part 14 with the metering opening 15. The outlet shaft 10 can, for example, be detachably fixed to the underside of the metering part 14 with the metering opening 15. For this purpose, in the illustrated embodiment, the outlet shaft 10 comprises a fastening device 21 with, on the one hand, two spaced-apart, e.g., U-shaped receptacles 22, 23, which are arranged on supports 24 projecting laterally from the circumferential wall 20 of the outlet shaft 10, in order to detachably engage the receptacles 22, 23, for example, with complementary bolts (not shown) on the underside of the metering part 14 with the metering opening 15. On the other hand, the fastening device 21 comprises, for example,a fastening bore 25 arranged at a lateral distance from the mountings 22, 23, which in turn serves to accommodate a screw or similar, in order to be able to fasten the outlet shaft 10 to the metering part 14.

[0028] For the sake of completeness, it should be noted here that the outlet shafts 10, 11 do not necessarily have to have a cross-sectional shape complementary to the metering opening 15, but can, for example, also correspond to the circumference of the outlet opening 12 (see the Fig. 2 and Fig. 3) may be arranged if the latter coincides with the metering opening 15. In particular, if the disc spreader does not have a device for shifting the point of application of the spreading material onto the distribution discs 3, 4 (not shown), the discharge opening and the metering opening may be one and the same opening at the bottom of the storage container 7 or a respective container part 8, 9.

[0029] How to continue, especially the Fig. 5 and Fig. 6, but also the Fig. As can be seen from Figure 4, the outlet shaft 10 has at least one opening 26 – in this case, three openings 26 – in the region of its (upper) end facing away from the distributor disc 3. These openings are arranged, for example, side by side in the circumferential direction at a height close to the mounting device 21 and serve for pressure equalization to prevent a suction effect inside the fully enclosed outlet shaft 10 when the distributor disc 3 is rotated. While the openings 26 in the embodiment shown in the drawing are primarily rectangular with rounded corners, they can, of course, also have practically any other geometric shape, such as round, oval, polygonal, etc.

[0030] The discharge chute 10 is further equipped at its free (lower) end facing the distributor disc 3 with elastically compliant material strips 28, such as bristles, bristle bundles, or the like, which also extend around the entire circumference of the discharge chute 10 in the direction of the distributor disc 3 and, in particular, up to directly above the distributor disc 3 or its throwing vanes 5. In the illustrated embodiment, the elastically compliant material strips 28 all have approximately the same length, with their ends being arranged, in particular, in a horizontal plane directly above the distributor disc 3 provided with the throwing vanes 5.While the elastically compliant material strips 28 may, for example, be made of a plastic material, in particular a wear-resistant one, the outlet shaft 10 with its circumferential wall 20 and the fastening device 21 is preferably made of a thermoplastic plastic material, and may in particular be designed in the form of an injection-molded part or a 3D-printed part.

[0031] Regarding the openings 26 in the perimeter wall 20 of the discharge shaft 10, their total area is dimensioned, for example, such that it comprises approximately 10% of the total perimeter area of ​​the discharge shaft 10—or more precisely, the perimeter wall 10 including the flexibly elastic material strips 28—so that sufficient pressure equalization is ensured to prevent a suction effect. For corresponding reasons, the openings 26—three in this case—extend by approximately one-quarter of the perimeter of the perimeter wall 20 of the discharge shaft 10. Furthermore, it may prove advantageous if the openings 26 are arranged in a circumferential region of the perimeter wall 20 of the discharge shaft 10 that is located—viewed in the direction of travel F (see the Fig. 2 and Fig.3) - extends to the front and / or laterally outer circumferential section of the discharge shaft 10, for example, by a circumferential section of the discharge shaft 10 of approximately 90° corresponding to one quarter of the circumferential area of ​​the circumferential wall 20, wherein this circumferential section extends with an arc length of approximately 90° from the front side of the discharge shaft 10 – viewed in the direction of travel F – to its laterally outer side. This ensures that at least one of the openings 26 – viewed in the direction of rotation or circumferential direction of a respective distributor disc 10 – is positioned downstream of the point of impact of the metered mass flow of distributed material onto the throwing blades 5 of the distributor disc 3, so that pressure surges caused by this are properly equalized through the openings 26 without any lateral deflection of the mass flow of distributed material that would result in a shift of the feed point. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2007 053 550 A1

[0004] DE 38 06 756 A1

[0006] EP 0 380 040 B1

[0006] DE 10 2012 024 363 A1

[0026]

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