Sieve belt unit for a harvester and associated flap unit

Description

[0001] The present invention relates to a sieve belt unit for a harvesting machine, in particular for a root crop harvester, for sieving out impurities from a mixture comprising harvested material and impurities, in particular in the form of soil, clods and stones, wherein the sieve belt unit comprises a sieve belt which has at least two endless supports, preferably designed as support belts or chains, between which sieve bars are arranged in a direction transverse to the conveying direction, which form a plurality of sieve bar units, in particular each comprising at least two sieve bars, wherein at least some of the sieve bars are fixed so as to be movable relative to the endless supports.

[0002] When harvesting and transporting root crops, especially potatoes, using a standard screening belt, unwanted impurities in the form of soil should be selectively removed either to protect the crop or, in addition, selectively removed from the crop-impurity mixture. At the same time, depending on the size of the crop being screened or transported, the goal is to prevent excessively small fractions of the crop from falling through the screening belt or being crushed during transport.

[0003] In DE 27 15 108 it was proposed to vary the screen belt pitch in such a way that additional cross bars are subsequently mounted on the existing screen belts, which lead to a variation in the screen belt pitch.

[0004] The additional cross bars have to be mounted individually, which involves a corresponding amount of effort.

[0005] From DE 3234 C it is known to position sieve bars at different angles to the sieve belt.

[0006] Furthermore, EP 133 886 A1 discloses a control device for a harvesting device which, in the event of a change in the position of the belt collecting device, can immediately initiate a correction of the position of the belt collecting device in order to return it to its originally set position so that optimal harvesting is possible.

[0007] Furthermore, drop flaps are known from the prior art and are integrated as additional components into a screening belt. The drop flaps are closed in the screening zone on the upper run and open due to gravity on the lower run. This creates larger recesses in the lower run, which improve the self-cleaning of the screening belt due to debris falling downwards from the upper run. The drop flap is closed on the load run and only opens due to gravity on the empty run. To change the screening belt pitch, i.e. the effective distance between the screening bars on the screening belt, the belt must be dismantled and replaced. The associated time expenditure during a harvesting operation, when time windows are often comparatively tight, is disadvantageous.

[0008] JP S48-39210 discloses a positioning means by which flap units protruding from one part of the upper run are prevented from doing so in a first part of the upper run. JP S44-17154 discloses flap units that are fixedly mounted on a screen bar.

[0009] The object of the present invention is to minimize the effort required to change the screen belt pitch.

[0010] The object is achieved by an object according to claim 1 and by an object according to claim 15. Advantageous embodiments of the invention can be found in the subclaims referring back to these claims and in the following description.

[0011] According to the invention, the screen belt unit comprises a positioning means arranged at least in sections along the screen belt and acting on the movable screen bars, by means of which a spacing of subsequent screen bars in the conveying direction in the screening zone, viewed in the screening direction, can be defined and, in particular, variably adjusted. The positioning means acts either directly or indirectly on the movable screen or transverse bars. It results in a relative position of the movable screen bars to the endless supports such that, viewed in the screening direction, the spacing of the screen bars (a movably arranged one and a particularly subsequent fixed screen bar) can be varied by changing the position of the positioning means.

[0012] By arranging the positioning means, which is not part of the screening belt, and by acting on the movable screening bars, the spacing between successive screening bars can be varied even within one and the same screening zone. For example, the positioning element can hold or guide the movable screening bars at a distance that varies, in particular increasing and / or decreasing, over the course of the screening zone when viewed in the screening direction. In this way, the separation of impurities from the crop is carried out in a targeted manner along the course of a screening zone as the conveying distance increases. The change in the spacing of subsequent screening bars in the conveying direction preferably goes hand in hand with the change in the spacing perpendicular to the conveying direction, which leads to the advantageous formation of pockets in the screening belt.

[0013] The inventive design of a screen belt unit with screen bar units, each of which preferably has one or more movably mounted screen bars, eliminates the need to replace the screen belts to change the screen belt pitch. The prior art also eliminates the need to attach additional screen or cross bars. The screen or cross bars of the device according to the invention include bars that run vertically between the two endless supports as well as those that may be slightly angled, and in particular, also offset screen bars.

[0014] Furthermore, it is understood that the endless supports can be opened in a conventional manner for maintenance and repair purposes, or even for replacement due to wear and tear, using known connecting means. For this purpose, the endless supports can be equipped with locks or other connecting areas that open the endless supports.

[0015] Advantageously, at least a portion of the sieve bar unit is configured to be positionally adjustable relative to the endless support by the positioning means. In this case, the sieve bar unit, in particular, has the sieve bar movably mounted relative to the endless support. Accordingly, a portion of the sieve bar unit is then configured to be positionally adjustable relative to the endless support. Preferably, the portion of the sieve bar unit that can be positioned in a positionally adjustable manner relative to the endless support is a flap portion, as described below, which can be pivoted or rotated about at least one portion of the sieve bar unit that is arranged relative to the endless support or fixed thereto.In particular, the pivotable or rotatable part of the screen bar unit, and thus the movable part of the same, is mounted on the positioning element downstream of the non-pivoting part of the screen bar unit in the direction of travel. This is advantageous for a pulling movement, as fewer blockages of the pivotable parts can occur when in contact with the positioning element. For an optional and particularly short-term reversing operation of the screen belt to clear any blockages, the pivotable or rotatable part can then also be mounted in advance.

[0016] According to a further embodiment of the invention, the sieve bar unit can have a sieve bar that is eccentrically mounted in cross-section. This can be an oval bar or a round bar, but one provided with an eccentrically mounted axis of rotation within its outer surface. When using these round bars, to vary the distance between successive bars, not every bar is adjusted, but for example only every second bar. Preferably, however, the sieve bar is mounted so that it can rotate or pivot about a pivot axis and is spaced from a rotation or pivot axis by a joint and any associated spacing means. Thus, already known sieve bars can be used according to the invention.

[0017] According to the invention, the screen bar unit is provided with at least one flap unit having at least one of the two screen bars, wherein the flap unit is pivotable or rotatable via at least one joint connected to the endless support, and the positioning means is designed to influence an angular position of the flap unit. The flap unit thus has the screen bar to be pivoted. The angular position results from an angle between the conveying direction and a longitudinal extension of the flap unit extending radially from the rotation or pivot axis. For example, in a screen bar unit with a screen bar attached to the endless support and a screen bar arranged such that it can pivot or rotate relative to it, this longitudinal extension is defined by a straight line passing through both longitudinal center axes of the screen bars and running perpendicular to the same screen bars, which straight line is angled relative to the conveying direction F.

[0018] Flap units according to the invention can be arranged one after the other or one behind the other in the conveying direction of the screen belt, so that the positioning means, which is arranged at least partially along the screen belt and in particular in the screening zone, simultaneously influences a plurality of flap units with regard to their angular bearings. Different angular positions due to different positions of the positioning means result in a different distance, viewed in the screening direction, on the one hand between the fixedly spaced screen bars of a screen bar unit and, on the other hand, between the screen bars of a first upstream and a downstream screen bar unit.

[0019] The screening direction is the direction of gravity, which acts on the impurities in such a way that they can fall through the spaces formed by the screen bars, provided they have the right dimensions.

[0020] According to a further development of the invention, the positioning means is designed in such a way that it limits the pivoting or rotation of the flap units, in particular due to gravity. It is therefore located below the movable parts of a screen bar unit or the flap unit and forms a support or a support surface for them. Thus, by resting the movable parts of a screen bar unit, an angular position can be defined which is associated with a specific screen belt pitch. If the positioning means is sufficiently far apart from the screen bar unit such that it is no longer in contact with the positioning means, the screen bar unit is then aligned due to gravity. In this position, the distance in the conveying direction of subsequent, iesuccessive screen bars, the pitch is maximal, at least in the case of a screening zone running horizontally to the substrate (and disregarding any asymmetries in the weight distribution of a flap unit). If the positioning means is arranged as tightly as possible along the endless support, the screening unit can pivot only slightly or not at all and has a horizontal or almost horizontal alignment and parallel to the conveying direction F. The screen bar spacing is then minimized.

[0021] Advantageously, the positioning means in the screening zone has at least one guide surface for positioning the flap units. Such a guide surface, which runs along the screening belt according to the arrangement of the positioning means, offers a structurally comparatively simple possibility for influencing a large number of screen bar units simultaneously. By moving such a guide surface, and thus the positioning means, closer to and further away from the screening belt, the pivoting or rotating flap units are given a range of motion that determines the angle of attack of the flap units and thus the screening belt pitch. Advantageously, the guide surface is arranged next to and in particular at least partially between the endless supports, viewed perpendicular to the conveying direction.Conventional screening belts can then be used without changing the installation space for the screening belt, with the positioning means simply being arranged along the screening zone inside the often existing air spaces of the screening belt frame and preferably being fixed in a variably positionable manner on the machine frame or the screening belt frame. In this way, existing harvesters can be retrofitted with the screening belt unit according to the invention.

[0022] In a further advantageous development of the screen belt unit, the guide surface is angled to the underlying surface, viewed in the conveying direction, preferably at an angle γ between 10° and 60°, and in particular is designed to slope downwards towards the center of the screen belt unit. This allows fewer unwanted impurities in the form of soil or clods to deposit on the guide surface. In particular, at the same height as the screen belt, on both sides along a center of the screen belt unit, there are guide surfaces that slope downwards towards this center, so that the guided screen bar units are centered and, at the same time, as little impurity as possible is deposited on the guide surfaces. The respective flap units are preferably provided with correspondingly adapted and complementarily inclined contact areas or surfaces for contact with the respective guide surfaces.

[0023] Preferably, the guide surface can be provided with a profile to generate a selectively varying spacing, i.e., a selectively varying screen belt pitch. This profile can be present, for example, in sections or across the entire guide surface of the positioning element for short pulses to assist cleaning purposes. Profiling can influence the spacing of the screen bars or the angular position of the flap units during operation, which in turn leads to a short, pulse-like raising or lowering of the transported mixture. A cleaning effect can be easily supported by such an induced shaking movement.

[0024] It goes without saying that the sieve bars can be provided with a plastic coating with damping properties, particularly—but not exclusively—to protect the crop. Furthermore, several sieve bars of a flap or sieve bar unit can be provided with the same covering, so that the spacing between the sieve bars of a sieve bar unit is reduced to zero.

[0025] In particular, the guide surface is part of a guide rail that is at least partially designed as a wear part. A part of the screen belt unit, for example, attached to the machine frame as a guide rail, thus has, in particular, a replaceable part in the form of one or more slide rails. This part is attached to the additional screen belt unit or to the machine frame or to the additional guide rail via appropriately detachable fastening means. In particular, the guide rail is provided with a plastic layer, for example, made of polyurethane, or is even made entirely of plastic.

[0026] In general, a screen bar is defined as a bar of any cross-section spanned between the endless supports. The cross-section can be round, non-round, and, in particular, flat.

[0027] For variable adjustment or to realize adjustability even during ongoing operation or during short changeover phases, according to the embodiment of the invention, at least one actuator is assigned to the positioning means, via which the distance of at least one part of the positioning means guiding the flap unit from the endless carrier can be adjusted. In particular, this varies at least the distance of the guide surface from the endless carrier. This distance then determines the angular position of the flap unit connected to the endless carrier, wherein the positioning means can bear against one or more parts of the flap unit, in particular comprising a joint part and / or a sieve bar. Threaded rods are preferably suitable as actuators, particularly for manual adjustment or adjustment controlled by stepper motors. Alternatively or additionally, hydraulically or pneumatically or generally electric motor-operated actuators can be used.These can be actuated in particular via a control or control and evaluation device belonging to the machine control system and in particular integrated into it.

[0028] By means of one or more actuators, which actuate positioning means acting in particular only on short sections of the screening belt, at least on one screening bar unit, a knocking action that supports the screening can be generated by means of an associated control or control and evaluation device.

[0029] Preferably, a positioning means is arranged at both the left and right ends of the respective screen bar units, viewed in the conveying direction, so that uniform guidance of the movable screen bars is achieved. Regardless of any partially integral connection of the positioning means to a guide of the respective endless supports that may be present on the frame side, a part of the positioning means that guides the screen bar units is arranged at a distance from the endless support.

[0030] The positioning means can advantageously be designed in multiple parts along the screening zone, allowing for the greatest possible variability in the spacing, particularly of the guide surface from the endless carrier. The guide surface can then also be designed in multiple parts and can accommodate changes in the pitch of the screening belt.

[0031] For example, a screen belt unit according to the invention equipped with flap units can be used in an ascending section of the screen belt by setting a specific angular position of the flap units to form conveyor pockets in the screen belt, while in more horizontally running conveyor sections, the focus can be on the screening function. For this purpose, different and, in particular, varying distances of the guide surface from the endless support and the associated different angular positions of the flap units and screen bar spacings can be set in the screen belt section with a screening function in the foreground. A screen belt unit according to the invention can thus have different focal functions along the course of its screening zone in the upper run.

[0032] In this respect, the screen belt unit according to the invention, in the case of a multi-part positioning means, also has, in particular, several adjusting means. While the screen bar units according to the invention can have slight changes in the spacing of the screen bars from one another, for example, via elongated holes, it is advantageous to avoid undesired positions and to define precise spacing if the screen bars of a screen bar unit have a fixed spacing from one another, except for any existing bearing play.

[0033] According to a further advantageous embodiment of the invention, a sieve bar of a respective sieve bar unit is fixed to the endless supports and forms part of two joints for connecting the flap unit. By fixing the sieve bar, a pivoting or rotating joint can be easily formed, which, via the pivoting or rotating joint parts, enables a movable sieve bar arranged parallel to the fixed sieve bar. It is expedient for the sieve bar unit to have a pivoting or swivel joint facing both outer endless supports. The sieve bar fixed to the endless support then forms the axis of rotation of the flap unit. Alternatively, for example, two pivoting sieve bars forming the flap unit can be mounted to one another and via a bent connection that does not form a sieve bar in a pivot bearing or rotary bearing of the respective endless supports.

[0034] In particular, the guide surface is part of a guide rail which, as a structurally relatively simple component, can be mounted to a frame of the screen belt or a machine frame by means of installation of a screen belt unit according to the invention in a harvesting machine and can in particular be subsequently attached.

[0035] To minimize wear between the pivotable screen bar unit part and the guide surface, the positioning means can also be designed to be at least partially co-rotating. In such a more complex design, the rotational speed of the positioning means, which can also be belt-shaped, for example, would be adjusted to the rotational speed of the screen belt. The positioning means would then also be designed to be variable in distance from the screen belt using appropriate positioning means.

[0036] Preferably, at least 25% of the screen bars are designed so that their position can be changed relative to the endless support, so that a screen belt has a variable screen pitch over large parts of its total length. More preferably, a screen belt unit according to the invention is further provided with a screen belt which is at least 50% provided with screen bars designed so that their position can be changed relative to the endless support. For example, every second screen bar can be stationary, while on each stationary screen bar there is arranged a flap unit with a screen bar which can be moved at a fixed distance but pivotally around the stationary screen bar. Designs of the screen belt unit according to the invention can preferably design up to 3 out of 4, i.e. 75%, of the screen bars to be position-variable, so that advantageous designs of the flap unit with two screen bars which can be pivoted around a fixed screen bar or with three pivotable screen bars can be used.

[0037] The preferred embodiments of the invention are provided with flap units which, at least within certain limits, can freely pivot or rotate about a rotational axis which is stationary relative to the endless supports and, in particular, the fixed sieve bars. To prevent unwanted folding over of the flap units, which can freely pivot between fixed sieve bars, in the region of deflections, one or more guide units can be provided precisely in these regions, which are arranged in addition to the positioning means and, in particular, viewed in a transverse direction, outside the area delimited by the endless support. These are preferably already known haulm intake rollers which, in the relevant region at the front in the direction of travel, prevent any flap units pivoting due to centrifugal force from unwanted folding over.

[0038] Preferably, a guide surface of the positioning means and an outer surface of a flap unit intended to rest against it are designed in parallel in order to ensure good guidance and a cleaning effect on areas of the positioning means which become contaminated by admixtures during operation.

[0039] An exemplary flap unit comprises a screen bar and has at least one joint part designed for releasable attachment to another screen bar of a previously or subsequently described screen belt unit, wherein the joint part or the screen bar of the flap unit has an outer surface designed for engagement with a positioning means. The joint part can be part of a film hinge or a rotary joint. While the positioning means preferably has an outer surface and guide surface provided with a plastic coating, the flap unit can advantageously have a surface designed parallel thereto in the various engagement positions, which ensures the best possible guidance. Furthermore, the widths of the guide surfaces are advantageously matched to the width of the engagement surfaces of the flap unit such that they differ in width by only a few centimeters (< 10 centimeters).This means that only a small amount of debris can be deposited on the guide surfaces of a positioning device and the guide surfaces are simultaneously cleaned during operation by the surrounding outer surfaces of the flap unit in the upper run.

[0040] For example, the joint part is at least two-part and designed to accommodate the additional screen bar of the screen belt unit, so that the replacement of individual damaged or worn flap units is easily possible. In particular, the joint part is then part of a pivot joint. Preferably, a sliding and / or locking element is provided for pivotally securing the joint part, particularly to a screen bar firmly connected to an endless support, so that the attachment and removal of a flap unit is as simple and quick as possible.

[0041] The joint parts provided for mounting on a sieve bar are preferably designed as joint shells and can either be provided in one piece with the positionally adjustable cross or sieve bar or have corresponding receiving areas for conventional sieve bars.

[0042] An exemplary screen belt comprises at least two endless supports, preferably designed as carrier belts or chains, between which screen bars are arranged in a direction transverse to the conveying direction, wherein a plurality of the flap units described above or below are present. In particular, such a screen belt, which also benefits from the respective advantages described above and below, is formed entirely by screen bar units including a corresponding flap unit.

[0043] Finally, the object is also achieved by a harvesting machine comprising a screen belt unit as described above or below. This machine benefits from the advantages of the screen belt unit described above and below. It is understood that this harvesting machine has the means necessary for operating the screen belt unit according to the invention, such as guide rollers or discs, drive means, frame or other supporting parts. In particular, the positioning means is fixed to the frame and can act on the movable screen bars via at least one correspondingly supported actuator.

[0044] According to a further development of the invention, the harvesting machine has a sensor for detecting the slope of the ground and an associated evaluation and control device. The harvesting machine, with its evaluation device, is designed to control the positioning device depending on the slope of the ground, particularly as viewed in the direction of travel. For example, the steeper the slope, the larger the pockets that can be formed by adjusting the positioning device through the successive sieve belt units.

[0045] These pockets, created by the downward folding, particularly in the rising sections of a screen belt, then counteract the gravity-induced rolling of the crop transported on the screen belt. Inclination sensors, in particular, can be used as sensors to detect the ground slope. The ground slope can be determined additionally or alternatively using one or more other sensors, e.g., using a GPS or similar position sensor in conjunction with a soil map stored locally in the control and evaluation device or externally on a server. The control and evaluation device comprises standard IT resources used in harvesting machines. It is preferably integrated into the machine control system.

[0046] Further advantages and details of the invention can be found in the following description of the figures. The figures show: Fig. 1: an object according to the invention in a perspective view, Fig. 2 a partial view of another object according to the invention in a side view, Fig. 3: the object according to Fig. 2 in a further operating position, Fig. 4: the object according to Fig. 2 in a further operating position, Fig. 5: the object according to Fig. 3 in a partial view, Fig. 6: a detail of a device according to the invention, Fig. 7: a further detail of a device according to the invention, Fig. 8: a further object according to the invention in a broken, slightly perspective view, Fig. 9: a detailed view of a further object according to the invention in a detailed view, Fig. 10: the object according to Fig. 9 in a further operating position, Fig. 11: the object according to Fig. 9 in a further operating position, Fig. 12 a-c views of a part of a further object according to the invention, Fig. 13 a-c views of a part of a further object according to the invention, Fig. 14 a cross section through a further embodiment according to the invention.

[0047] Individual technical features of the exemplary embodiments described below can also be combined with previously described exemplary embodiments as well as the features of the independent claims and any further claims to form subject matter according to the invention. Where appropriate, elements that are at least partially functionally equivalent are provided with identical reference numerals.

[0048] A screen belt unit 1 according to the invention comprises Fig. 1 a screening belt 2 which is intended for screening out impurities from a mixture of crop material and impurities. The screening belt 2 has two endless supports 3 designed as carrier belts, between which screening bars 4 and 6 are arranged in a direction transverse to the conveying direction. The conveying direction F has different gradients compared to a horizontal line (not shown) over the course of a screening zone S formed by the upper run of the screening belt 2. These gradients result from the positioning of deflection rollers or pulleys 7, some of which can be designed as drive pulleys. A tensioning roller 8 tensions the screening belt 2 against a drive pulley 9 so that, depending on the set gradient of the screening belt, sufficient contact with the drive roller 9 is present in the individual screening belt zones.

[0049] Individual sieve bars 4 and 6, which are explained in more detail below, form sieve bar units 11 (cf. Fig. 6 ) which have a sieve bar 4 fixed to the sieve belt 2 and a sieve bar 6 fixed to it in an articulated manner, including an associated articulated part 12.

[0050] The screen bars 6 are movably mounted relative to the endless supports 3 via the rotary or pivot joints formed between and through the screen bars 4. Along the screen belt 2, several positioning means 13 are arranged both on the left side in the conveying direction and on the right side in the conveying direction, which act on the movable screen bars 6 in such a way that a distance A (cf. Fig. 9 bis 11 ) and is variably adjustable by actuators. In particular, the distance A can vary over the length of the screening zone in the conveying direction F.

[0051] The positioning means 13 is designed as a guide rail and is made up of several parts, so that individual sections of guide rails 13 are created analogously to the individual pitch sections of the screen belt 2. With a plurality of associated actuators 14 ( Fig. 2 ), the individual sections or parts of the positioning element 13 can be brought into the desired relative position to the endless carrier 3. In order to be able to make the necessary adjustments for different gradients of the screening belt in the course of the screening zone S, the multi-part positioning element 13 is provided with a series of sliding connections that can be moved by means of elongated holes. The individual parts of the positioning element are thus guided into one another and can thereby be moved towards or away from one another in order to be able to change the overall length of the positioning element 13 in the upper run or the corresponding screening zone S. Figuren 2 bis 4 Furthermore, usual parts of a harvesting machine according to the invention can be seen.

[0052] In the Figuren 2 , 3 and 4 9, 10, and 11 illustrate the different screen belt pitches and spacings A due to different relative positions of the positioning element 13 or parts of the positioning element 13 with respect to the endless support 3. By spacing the positioning elements 13, which are arranged at least partially between the endless supports 3 in a plan view, from the endless support 3, the individual flap units of the screen bar units can assume a different angular position relative to the longitudinal extent of the endless support 3 or to the respective conveying direction. This changes the spacing A between successive screen bars 4, 6 of different screen bar units.

[0053] The positioning means 13 arranged on the left and right inside of the endless supports 3 along the screen belt 2 limit the gravity-induced pivoting or rotation of the movable parts of the screen bar units 11 or the flap units until the opening is maximized as described above for horizontal runs of the screen belt 2 due to insufficient contact with the support ( Fig. 11 To limit the pivoting or rotation of the flap units due to gravity, the positioning means 13 in the screening zone is provided with a guide surface 16, on which, in the illustration of the Fig. 5 The undersides of the hinged parts 12 of the flap units, comprising screen bars 6 and the hinged part 12, rest on the guide surface (not shown in detail). The surface 16 is provided with a plastic coating to reduce friction with the undersides of the flap units. During operation of the screen belt unit according to the invention, the flap units are cleaned of debris falling from the upper run by sliding or sliding along the guide surface.

[0054] The flap units according to the invention can be Fig. 8 at both ends have joint parts 12 which are connected by the sieve bar 6 shown in broken form. The sieve bars 4 of a respective sieve bar unit 11 are fixed to the endless support, so that the sieve bar 6 is fixed in a variable position relative to the endless support 3 via the joint formed between the sieve bar 4 and the sieve bar 6 (cf. Fig. 5 and 6). For maintenance purposes, a joint part 12 is preferably designed with two shell halves 18 ( Fig. 7 ), which are connected to each other via fastening means 15. A faulty, damaged, or worn flap unit can be replaced quickly.

[0055] The angular position of the flap unit or the screen bar unit is as shown in the Fig. 9 , 10 and 11 shown in the screening zone S by the distance of the positioning means 13 and in particular its guide surface 16 from the screen belt carrier 3. In the maximum tight position according to Fig. 9 an angle W between a straight line 19 formed parallel to the conveying direction F and thus to the endless carrier 3 and a straight line 20 formed by the longitudinal extension of a flap unit is almost 0 ( Fig. 9 ). Due to the spacing of the positioning means 13 from the endless support or the axis of rotation of the fixed sieve bars 4, the flap units can open to a larger angle W due to gravity and possibly loaded by the mixture to be sieved and continue to rest on the guide surface 16 ( Fig. 10 ). The greater spacing of the positioning means 13 from the axis of rotation of the respective fixed sieve bar of a respective flap unit leads to Fig. 11 The horizontal alignment of the screen belt 2 shown in FIG. 1 results in the joint parts 12 no longer resting on the guide surface 16 and the flap parts being pivoted open to their maximum extent. The angle W assumed for this purpose is, depending on the symmetry of the flap unit, almost 90°, but at least preferably between 80° and 100°. In order to prevent the flap units from tipping over due to gravity in the area of ​​the deflection of the endless supports 3 or the screen belt 2, a roller conventionally designed as a haulm intake roller, which is preferably wider than the endless support, can be present in the deflection area ( Fig. 2 ).

[0056] One to the flap unit after Fig. 6 An alternative flap unit according to the invention has a joint part 12 which has a push and / or locking element 22 for pivotally fixing the joint part, in particular to a screen bar firmly connected to an endless carrier, by means of which the fastening and disassembly of a flap unit is carried out as simply and quickly as possible ( Fig. 12 a-c ). Instead of the screw connections of the joint part 12 according to Fig. 6 This joint part as well as the joint part according to the Fig. 13 a-c provided with a locking and / or sliding element, which is either on the front side ( Fig. 12 a) or sideways ( Fig. 13 a) is inserted into a main part 23 of the joint part and locked there via undercuts 24 ( Fig. 12 b) or is secured ( Fig. 13 b) .

[0057] The respective locking and / or pushing element 22 is preferably made of a harder material than the rest of the joint part 12 in the area of ​​contact with a sieve bar, so that the locking and / or pushing element 22 absorbs the essential forces acting on the flap unit and passes them on to the generally stationary sieve bar on which the flap unit is arranged.

[0058] The locking and / or pushing element 22 forms for the preferably fixed sieve bar together with the rest of the joint part 12 a cross-section according to Fig. 12 b or Fig. 13 b The locking and / or sliding elements 22 of the embodiments of the Fig. 12 and 13 provided with a receptacle 24 which is half-shell-shaped in cross-section, the inner surface of which, together with a correspondingly shaped receptacle 25 of the main part 23, forms the bearing seat for the respective sieve bar.

[0059] In a further embodiment of a screen belt unit according to the invention, this is provided with two guide surfaces 16 which, in the cross section of the Fig. 14 and, viewed in the conveying direction, are angled to the subsurface at an angle γ and are designed to slope downwards toward the center M of the screening belt unit. This allows fewer unwanted impurities in the form of soil or clods to deposit on the guide surfaces. At the same time, the flap unit is centered on the outer surface of the joint parts 12 with the correspondingly adapted and complementarily inclined joint part guide surfaces 16.1.

Claims

1. Sieve belt unit for a harvesting machine, in particular for a root crop harvester for sieving off admixtures of a mixture of crop and admixtures, comprising a sieve belt (2) with at least two endless carriers (3), preferably in the form of carrier belts or chains, between which sieve bars are arranged transversely to the conveying direction, which form a plurality of sieve bar units (11), in particular each comprising at least two sieve bars (4, 6), at least some of the sieve bars being movably fixed relative to the endless carriers (3), wherein the sieve belt unit (1) has a positioning means (13) which is arranged at least in sections along the sieve belt (2) and acts on the movable sieve bars (6) and by means of which a spacing A in the conveying direction F of subsequent sieve bars is defined and variably adjustable in the sieving zone S as viewed in the sieving direction, characterized in that each sieve bar unit (11) has at least one flap unit with at least one of the two sieve bars (4, 6), the flap unit is pivotable or rotatable by means of at least one joint connected to the endless carrier (3), and the positioning means (13) is designed for affecting an angular position of the flap unit, and wherein at least one actuator (14) is associated with the positioning means (13), by means of which the distance of at least one part of the positioning means (13) guiding the flap unit from the endless carrier (3) can be adjusted.

2. Sieve belt unit according to claim 2, characterized in that at least one part of the sieve bar unit (11) is designed so that its position relative to the endless carrier (3) can be changed by the positioning means (13).

3. Sieve belt unit according to one of the preceding claims, characterized in that the sieve bar unit (11) has a sieve bar which is mounted eccentrically in cross-section.

4. Sieve belt unit according to claim one of the preceding claims, characterized in that the positioning means (13) is designed to limit a particularly gravity-induced pivoting or rotation of the flap units.

5. Sieve belt unit according to one of the preceding claims, characterized in that the positioning means (13) has at least one guide surface (16) in the sieving zone S for abutment of the flap units.

6. Sieve belt unit according to claim 5, characterized in that the guide surface (16), viewed in the conveying direction, is angled towards a subsurface and in particular slopes down towards the center (M) of the sieve belt unit.

7. Sieve belt unit according to claim 5 or 6, characterized in that the guide surface (16) is arranged next to and in particular between the endless carriers (3) when viewed perpendicular to the conveying direction.

8. Sieve belt unit according to one of claims 5 to 7, characterized in that the guide surface (16) is provided with a profiling to produce a selectively variable distance A.

9. Sieve belt unit according to one of the preceding claims, characterized in that the positioning means (13) in the sieving zone is formed in several parts.

10. Sieve belt unit according to one of the preceding claims, characterized in that the sieve bars (4, 6) of a sieve bar unit (11) have an at least substantially fixed spacing from one another.

11. Sieve belt unit according to one of the preceding claims, characterized in that a sieve bar (4) of a respective sieve bar unit (11) is fixed to the endless carriers (3) and forms part of two joints for connecting the flap unit.

12. Sieve belt unit according to one of the preceding claims, characterized in that the positioning means (13) is designed to move with the sieve belt.

13. Sieve belt unit according to one of the preceding claims, characterized in that at least 25%, preferably 50% and in particular up to 75% of the sieve bars (6) are designed to be adjustable in position relative to the endless carrier (3).

14. Sieve belt unit according to one of the preceding claims, characterized by a guide unit (21) limiting the change in position particularly induced by centrifugal force.

15. Harvesting machine, characterized by a sieve belt unit according to one of claims 1 to 14.

16. Harvesting machine according to claim 15, characterized in that the harvesting machine has a sensor for detecting the inclination of the ground and an associated evaluation and control device, the harvesting machine with its evaluation device being designed to control the positioning means as a function of the ground inclination.