DOUBLE DISC SPREADER WITH A BORDER SPREADER

Description

[0001] The invention relates to a twin-disc spreader with two distributor discs driven in opposite directions about parallel axes and with a boundary spreading device which, in its operating position, is arranged centrally between the distributor discs and has two essentially vertically arranged main guide surfaces which diverge symmetrically to the longitudinal axis of the twin-disc spreader from a point arranged between the distributor discs obliquely outwards and - viewed in the longitudinal direction of the twin-disc spreader - away from the distributor discs.

[0002] Twin-disc spreaders of the aforementioned type are known in various designs, particularly in the form of so-called centrifugal or rotary spreaders, for agricultural purposes, for spreading powdery or particulate materials, such as fertilizers or seeds. These spreaders are available in a wide variety of configurations, for example, in trailed versions or those mounted on the three-point linkage of a tractor. Such twin-disc spreaders comprise a hopper for receiving the material, at the bottom of which two discharge openings are typically arranged. Each discharge opening is equipped with a metering device to extract the desired quantity—or more precisely, the desired mass flow—of the material to be spread from the hopper.The metering unit typically includes a metering slide, which can be opened and closed by means of a suitable control device. This allows the desired mass flow rate to be adjusted depending on the desired distribution width of the material on the ground, the driving speed, and the physical properties of the material, such as its flowability. Alternatively, the metering unit can also include, for example, a controllable rotary cam or rotary roller for the same purpose. Downstream of each metering unit is a distribution disc, which is usually equipped with throwing vanes and serves to distribute the powdered or particulate material over the desired working width.The distributor discs, which are usually driven around vertical axes of rotation, generally rotate in opposite directions, with the distributor disc on the right in the direction of travel rotating counterclockwise and the distributor disc on the left in the direction of travel rotating clockwise when viewed from above.

[0003] In the case of winter service spreading machines, the container primarily serves to hold usually granular grit, sand and / or road salt, whereby the function of such a winter service spreading machine largely corresponds to that of an agricultural twin-disc spreader described above.

[0004] In agriculture, a uniform spreading density is achieved through the overlapping of the spreading patterns deposited by the distribution discs when driving over adjacent tramlines, a process known as normal spreading. The material is distributed evenly by the distribution discs on both sides of the twin-disc spreader, but with varying spreading densities that decrease from the inside out. Flat-sided spreading patterns, particularly trapezoidal or triangular shapes, are especially suitable for achieving a uniform spreading density. When driving over adjacent tramlines, the spreading patterns overlap in such a way that a uniform distribution across the entire working width is achieved.Such spreading patterns, desirable in normal spreading, lead to insufficient fertilization at the field boundary, where spreading is only done on one side and consequently no overlap occurs. This can happen if spreading only extends to the field boundary, or alternatively, if spreading over the boundary and beyond the field edge results in corresponding fertilizer losses. In many cases, such overspreading must be avoided altogether, for example, if the seed or crop in the neighboring field requires no or a different nutrient supply, or if a body of water or road runs along the boundary. The same applies to obstacles within the field that should not or must not be fertilized, such as groups of trees, bushes, bodies of water, rock formations, or the like.

[0005] To ensure a uniform spreading density when spreading along field boundaries and to prevent over-spreading, a steep-sided spreading pattern must be maintained on the boundary side of the twin-disc spreader, while the usual flat spreading pattern must be maintained towards the center of the field. To achieve this boundary spreading challenge, special boundary spreading discs can be used, or the spreading vanes on the distribution disc facing the boundary can be changed or adjusted. With multiple working widths, several boundary spreading discs must be available for border spreading, or the spreading vanes must be adjusted differently, which proves to be both time-consuming and cumbersome from a handling perspective.

[0006] In modern twin-disc spreaders, whose distribution discs are independently speed-controlled and / or equipped with a device for adjusting the point at which the material is applied to each distribution disc, it is also known to ensure border or edge spreading by reducing the rotational speed of the drive of the distribution disc closest to the boundary and / or shifting its point of application, either essentially circumferentially against the direction of rotation of the distribution disc closest to the boundary, or essentially radially outwards. However, this requires a twin-disc spreader equipped with the appropriate devices, and it only allows for a limited degree of precise spreading pattern that drops off abruptly at the field boundary.

[0007] For smaller or more cost-effective twin-disc spreaders, mechanical boundary spreading devices in the form of so-called boundary spreading screens are known. These can be permanently attached to the spreader or moved from a transport and rest position, in which they cannot come into contact with the material particles thrown by the spreading discs, into an operating position. In this operating position, they reduce the spreading width of the boundary spreading disc by reflecting some of the material particles thrown by it back towards the field interior. Such boundary spreading devices, for example, have a number of vertical guide surfaces whose primary function is to deflect the material particles leaving the spreading disc towards the field boundary.For this purpose, the guide surfaces can be shaped differently depending on their position relative to the respective distributor disc, for example, curved or bent at different angles. Such boundary spreading devices are designed for mounting on the side of a distributor disc facing a field boundary, i.e., in the area of ​​the corners of the twin-disc spreader, so that the spreading width of the distributor disc facing the field boundary is narrowed on the one hand, and its spreading pattern slopes more steeply on the other.

[0008] Furthermore, boundary spreading devices of this type are known which, in their operating position, are arranged centrally between the distribution discs and have two essentially vertically arranged main guide surfaces that diverge symmetrically to the longitudinal axis of the twin-disc spreader from a point located between the distribution discs, obliquely outwards and – viewed in the longitudinal direction of the twin-disc spreader – away from the distribution discs. When spreading at the boundary or edge using such a boundary spreading device, the metering element of the distribution disc facing the field edge is completely deactivated, and the boundary spreading device serves to limit the spreading pattern of the distribution disc facing away from the field edge, so that the latter does not throw the material beyond the field edge in the direction of the other (stationary) distribution disc.During such border or edge spreading, the twin-disc spreader travels relatively close to the field boundary, for example along a tramline near the field edge or along the headland. The border spreading device must ensure the most uniform distribution possible of the material up to the field edge, but not beyond it (the spreading pattern is steeply sloped and drops off sharply towards the field edge). In contrast, towards the interior of the field, a spreading pattern corresponding to normal spreading, largely unaffected by the border spreading device, must be achieved (the spreading pattern slopes gently towards the interior of the field). Such a border spreading device for a twin-disc spreader is known, for example, from DE 93 06 605 U1.

[0009] FR 1 400 911 A describes a twin-disc spreader with a similar boundary spreading device, which, in its operating position, is arranged centrally between the distribution discs and has two vertically arranged main guide surfaces. These guide surfaces are arranged symmetrically to the longitudinal axis of the twin-disc spreader and extend outwards and rearwards from a point located between the distribution discs, parallel to a circumferential section of the respective distribution disc. Each main guide surface of the boundary spreading device extends outwards and rearwards parallel to the circumference of the distribution disc to a point where the imaginary horizontal line connecting this point to the axis of rotation of the respective distribution disc forms an angle of approximately 10° with an imaginary horizontal line intersecting the respective axis of rotation of the respective distribution disc and extending in the longitudinal direction of the twin-disc spreader.

[0010] However, a disadvantage of such boundary spreading devices is that, when spreading at the boundary or edge, the only active spreading disc, namely the one facing away from the field edge, does not achieve a sufficiently steep spreading pattern, so that either there is an undersupply of material in the edge area of ​​the field or proportions of the material are thrown over the field edge, which should be avoided for the reasons mentioned above.

[0011] The invention is therefore based on the objective of further developing a boundary spreading device of a twin-disc spreader of the type mentioned above in a simple and cost-effective manner in such a way that, while at least largely avoiding the aforementioned disadvantages of boundary or edge spreading, a more uniform lateral distribution can be achieved right up to the edge of the field, while at the same time ensuring that practically no material is thrown beyond the edge of the field.

[0012] According to the invention, this problem is solved in a twin-disc spreader of the type mentioned above, equipped with such a boundary spreading device, by the fact that Each main guide surface of the boundary spreading device extends obliquely outwards to a point and – viewed in the longitudinal direction of the twin-disc spreader – away from each distributor disc, the imaginary horizontal connecting line with the axis of rotation of the respective distributor disc forming an angle of at most 30° with an imaginary horizontal line intersecting the respective axis of rotation of the respective distributor disc and extending in the longitudinal direction of the twin-disc spreader, and each main guide surface of the boundary spreading device has at least one through-opening arranged at a distance from the end of the respective main guide surface furthest from the twin-disc spreader, which are arranged symmetrically with respect to the longitudinal axis of the twin-disc spreader.

[0013] The embodiment according to the invention therefore provides, on the one hand, that the main guide surfaces of the boundary scattering device extend significantly further obliquely outwards around a respective distributor disc compared to the prior art, up to a point for which the following condition applies: an imaginary horizontal connecting line between the point to which a respective main guide surface of the boundary spreading device extends from the twin-disc spreader and the axis of rotation of the respective distribution disc, and an imaginary horizontal line intersecting the respective axis of rotation of the respective distribution disc and extending in the longitudinal direction of the twin-disc spreader They are arranged at an angle of no more than approximately 30°. In this way, the spreading pattern of the distributor disc facing away from the field edge is shifted further away from the field edge during boundary or edge spreading, and in particular, it is prevented that significant proportions of the spread material are thrown beyond the field edge.

[0014] Since it is difficult in this way to ensure uniform lateral distribution in the track of the twin-disc spreader or – if desired – over a certain width beyond the track to the field edge, the embodiment according to the invention provides, on the other hand, that the main guide surfaces of the boundary spreading device each have at least one through-opening arranged at a distance from the end of the respective main guide surface furthest from the twin-disc spreader, which ensures a locally limited passage of a portion of the material thrown by the distribution disc, so that the track or – if desired – a field edge section beyond the track can also be supplied with the predetermined target distribution quantity of material.Surprisingly, it was found that it is thus possible to achieve a very uniform lateral distribution right up to the field edge by means of a spreading pattern that drops off abruptly at the field edge and has extremely steep slopes, without any significant proportion of the material being thrown beyond the field edge. The through-openings of the main guide surfaces of the boundary spreading device according to the invention, as well as the main guide surfaces themselves, are arranged symmetrically with respect to the longitudinal axis of the twin-disc spreader, so that the boundary spreading device is equally suitable for spreading at the edge of a field located to the left of the twin-disc spreader (the metering element of the left distribution disc is deactivated in this case) as for spreading at the edge of a field located to the right of the twin-disc spreader (the metering element of the right distribution disc is deactivated in this case).

[0015] It should be noted at this point that the terms relating to the arrangement of the border spreading device or parts thereof, such as "vertical", "horizontal", any angle specifications and the like, always refer within the scope of the present disclosure to the operating position of the border spreading device in which it is able to fulfill its intended function.

[0016] To avoid over-spreading beyond the field edge with the greatest possible certainty when spreading at edges or borders, each main guide surface of the border spreading device advantageously extends obliquely outwards to a point and – viewed in the longitudinal direction of the twin-disc spreader – away from each distribution disc, whose imaginary horizontal connecting line with the axis of rotation of the respective distributor disc with an imaginary horizontal line intersecting the respective axis of rotation of the respective distributor disc and extending in the longitudinal direction of the twin-disc spreader an angle of at most about 20°, preferably of at most about 15°, in particular of at most about 10°, most preferably includes between about 2° and about 10°, such as between about 4° and about 10°.

[0017] To prevent at least portions of the material being spread, which is usually thrown obliquely upwards and largely tangentially from the respective distribution disc (which is typically equipped with throwing blades), from being flung over a respective main guide surface towards the field edge, a cover guide surface is advantageously attached to the upper end of each main guide surface of the boundary spreading device. This cover guide surface extends outwards at an angle of approximately 90° to approximately 150°, in particular between approximately 90° and approximately 135°, such as between approximately 90° and approximately 120°, with respect to the respective main guide surface.

[0018] The width of each guide surface can increase, particularly with regard to the fact that the particles being spread are thrown in a "particle cloud" of increasing volume as they move further away from the spreader, from the end closest to the twin-disc spreader towards the end furthest from the twin-disc spreader.

[0019] In order to arrange the main guide surfaces of the boundary spreading device partially around the distributor discs, i.e., obliquely outwards from the point located between the distributor discs and – viewed in the longitudinal direction of the twin-disc spreader – away from the distributor discs, the angle formed between the two main guide surfaces of the boundary spreading device expediently increases from the end near the twin-disc spreader towards the end furthest from the twin-disc spreader, which can be done in several stages, whereby outwards bent or curved sections of the main guide surfaces are also conceivable in principle.

[0020] With regard to the geometry of the main guide surfaces of the boundary spreading device, it can advantageously be provided that the angle formed between the two main guide surfaces on the section of the main guide surfaces near the twin-disc spreader is less than about 15°, in particular less than about 10°, preferably less than about 5°, wherein the two main guide surfaces of the boundary spreading device can be arranged in a substantially parallel manner on their sections near the twin-disc spreader, i.e., approximately between the two distributor discs.

[0021] The angle formed between the two main guide surfaces of the boundary spreading device on the section of the main guide surfaces furthest from the twin-disc spreader can, however, advantageously be between about 80° and about 130°, in particular between about 90° and about 120°, preferably between about 100° and about 110°.

[0022] Furthermore, it has proven advantageous if the sections of the two main guide surfaces furthest from the twin-disc spreader, which are arranged at an angle between approximately 80° and approximately 130°, in particular between approximately 90° and approximately 120°, preferably between approximately 100° and approximately 110°, to each other, extend over at least 30%, in particular over at least 35°, preferably over at least 40%, e.g. between approximately 40% and approximately 50%, of the total length of each respective main guide surface, so that they are noticeably longer than the other sections of the main guide surface of the boundary spreading device, which are arranged at smaller angles.

[0023] The main guide surfaces of the boundary spreading device can furthermore have at least one first central section between their sections closest to and furthest from the twin-disc spreader, wherein the first central sections of the main guide surfaces are arranged at an angle of between approximately 10° and approximately 30°, in particular between approximately 12° and approximately 26°, preferably between approximately 14° and approximately 22°, e.g., between approximately 16° and approximately 20°, to each other. The first central section of each main guide surface can, for example, adjoin its section closest to the twin-disc spreader.

[0024] Furthermore, the main guide surfaces of the boundary spreading device can each have at least one second central section between their sections closest to and furthest from the twin-disc spreader, wherein the second central sections of the main guide surfaces are arranged at an angle of approximately 25° to approximately 65°, in particular between approximately 30° to approximately 60°, preferably between approximately 35° and approximately 55°, e.g., between approximately 40° and approximately 50°, to each other. The second central section of each main guide surface can, for example, connect to the first central section (at its end furthest from the twin-disc spreader) and / or to the section of the respective main guide surface furthest from the twin-disc spreader.

[0025] According to an advantageous embodiment, at least one, and in particular at least two, short outer auxiliary guide surfaces are arranged on the opposite sides of the two main guide surfaces of the boundary spreading device. These auxiliary guide surfaces extend obliquely upwards and outwards from the lower end of each main guide surface, at an angle of approximately 30° to approximately 60°, in particular between approximately 35° and approximately 55°, preferably between approximately 40° and approximately 50°, with respect to the respective main guide surface. They are positioned on the main guide surfaces symmetrically with respect to the longitudinal axis of the twin-disc spreader.

[0026] The length of the outer auxiliary guide surfaces – considered in the direction of extension of the main guide surfaces – is preferably at most about 20%, in particular at most about 15%, preferably between about 5% and about 10%, of the total length of each main guide surface.

[0027] With regard to the arrangement of the auxiliary guide surfaces on the main guide surfaces of the border spreading device, it may preferably be provided that at least Each outer auxiliary guide surface is arranged at the end of a respective main guide surface furthest from the twin-disc spreader, e.g., at or in the region of its free end; and / or each outer auxiliary guide surface is arranged on the section of a respective main guide surface furthest from the twin-disc spreader, which form the largest angle between them, but are arranged at a distance from the end of a respective main guide surface furthest from the twin-disc spreader, e.g., substantially in the central region of the section of a respective main guide surface furthest from the twin-disc spreader; and / or each outer auxiliary guide surface is arranged on at least one central section of a respective main guide surface, which are arranged at an angle between approximately 10° and approximately 65°, in particular between approximately 10° and approximately 30°, to each other. In the latter case, the respective outer auxiliary guide surface can be arranged closer to the end of a respective main guide surface that is closer to the twin-disc spreader than to its end that is farther from the twin-disc spreader, i.e., closer in the direction of the distribution discs.

[0028] With regard to the through-openings formed in the main guide surfaces of the boundary spreading device according to the invention, in order to achieve optimal distribution in the direction of the driving path of the twin-disc spreader, as explained above, it is advantageous to arrange a first through-opening of each main guide surface of the boundary spreading device on at least one central section of each main guide surface, wherein the central sections of the boundary spreading device provided with the first through-openings are arranged at an angle between approximately 10° and approximately 65°, in particular between approximately 10° and approximately 30°, to each other.The respective first through-opening can be arranged, in particular, closer to the end of a respective main guide surface closest to the twin-disc spreader than to its end furthest from the twin-disc spreader, i.e., closer in the direction of the distributor discs, wherein it can preferably be arranged on the first central section of the main guide surfaces or most preferably in the area of ​​the end furthest from the twin-disc spreader of the first central section of the main guide surfaces, which are arranged at an angle between about 10° and about 30°, in particular between about 12° and about 26°, preferably between about 14° and about 22°, to each other.

[0029] In a further advantageous embodiment, it may be provided, alternatively or in particular additionally, that a second through-opening of each main guide surface of the border spreading device is provided for the aforementioned purposes. on at least one central section of a respective main guide surface, wherein the central sections are arranged at an angle between approximately 30° and approximately 60° to each other, and / or on the section of a respective main guide surface furthest from the twin-disc spreader in the region of the end opposite the free end of the section of a respective main guide surface furthest from the twin-disc spreader is arranged.

[0030] The respective second through-opening can extend, in particular, from the central section of a respective main guide surface adjacent to the section furthest from the twin-disc spreader, such as the second central section of a respective main guide surface described above, to the adjacent area of ​​the section of a respective main guide surface furthest from the twin-disc spreader. A respective second through-opening can, for example, be directly connected to the first through-opening of a respective main guide surface. Alternatively or additionally, a respective second through-opening can, for example,essentially over the entire second central section of each main guide surface, which are arranged at an angle between about 25° and about 65°, in particular between about 30° and about 60°, preferably between about 35° and about 55°, to each other, extending into the area adjacent to this of the section furthest from the twin-disc spreader of each main guide surface, which are arranged at an angle between about 80° and about 130°, in particular between about 90° and about 120°, preferably between about 100° and about 110°, to each other.

[0031] To enable the boundary spreading device according to the invention to be adjusted to the position of the field boundary up to which spreading is to take place, an advantageous embodiment provides that the opening cross-section and / or the position of at least one through-opening, in particular the second through-opening, of a respective main guide surface of the boundary spreading device is adjustable. By changing the cross-section and / or the position of the at least one through-opening, it is thus possible to treat either only a part or the entire driving lane of the twin-disc spreader on the side facing the field edge, or, preferably, to spread beyond the driving lane with the through-opening fully open, always producing a very steep-sided spreading pattern without throwing beyond the field boundary and without the driver having to maintain a precisely predetermined distance to the field boundary during the spreading operation.

[0032] The at least one through-opening, such as the second through-opening, can advantageously be at least partially closed by means of a slide guided on the respective main guide surface, so that when the slide is adjusted, both the opening cross-section and the position of the through-opening on the respective main guide surface are changed. The slide can, in particular, be displaceable between an open position, in which it is located at the end of the through-opening furthest from the twin-disc spreader, and an at least partially closed position, in which it closes at least a partial cross-section of the through-opening furthest from the twin-disc spreader, so that the slide is effective from the end of the through-opening furthest from the twin-disc spreader (fully open position) towards the end of the through-opening near the twin-disc spreader (partially or completely closed position).

[0033] The slide can preferably be assigned a scale identifying different, partially closed positions of the slide, which indicates, for example, what proportion of the track of the twin-disc spreader or what width beyond it is spread when the slide has been moved into the corresponding position.

[0034] In the course of scattering tests, it has also proven advantageous if each main guide surface of the limit scattering device has at least one first through-opening and at least one second through-opening, the distance between which – considered in the direction of extension of each main guide surface – is in particular at most 30 cm, in particular at most 20 cm, preferably at most 10 cm, wherein at least the through-opening arranged closer to the end of the limit scattering device facing away from the twin-disc spreader, i.e. the second through-opening, should preferably be at least partially closable for the reasons stated above.

[0035] In order to achieve a very uniform lateral distribution even within the track of the twin-disc spreader or, if necessary, also towards the field edge beyond this, it can be advantageously provided that at least one pair of the at least one through-openings of a respective main guide surface of the boundary spreading device is assigned at least one common central auxiliary guide surface, which is arranged on the side of the respective pair of through-openings facing away from the twin-disc spreader and extends between the main guide surfaces at an angle between 30° and 60°, in particular between 35° and 55°, preferably between 40° and 50°, with respect to a horizontal plane between the main guide surfaces from an upper area of ​​the main guide surfaces near the respective through-opening to a lower area of ​​the main guide surfaces far from the respective through-opening.The function of the central auxiliary guide surface(s), similar to that of the outer auxiliary guide surfaces, is primarily to reflect the material particles that have passed through the opening(s) obliquely downwards towards the ground, but within the path of the twin-disc spreader. The central auxiliary guide surfaces can advantageously be arranged at a certain distance from the respective opening towards the end of the boundary spreading device furthest from the twin-disc spreader.

[0036] Furthermore, with regard to a very uniform lateral distribution, even within the track of the twin-disc spreader or, if necessary, also towards the field edge beyond this, it has proven advantageous if at least one pair of the at least one through-openings of a respective main guide surface of the boundary spreading device is assigned two vertical guide surfaces converging towards the end of the boundary spreading device facing away from the twin-disc spreader, which are arranged between the two main guide surfaces on the side of the respective pair of through-openings facing away from the twin-disc spreader and are fixed, for example, on the sides of the main guide surfaces facing each other.The guide surfaces arranged between the main guide surfaces connect in particular to a respective through-opening in the direction of the end of the border spreading device furthest from the twin-disc spreader and guide the material particles passing through the respective through-opening, because they converge in the direction of the end of the border spreading device furthest from the twin-disc spreader, obliquely away from the respective main guide surface in the direction of the central area of ​​the lane.

[0037] In this context, it proves advantageous if the at least one common central auxiliary guide surface is arranged between the two vertical guide surfaces converging towards the end of the boundary spreading device furthest from the twin-disc spreader, and in particular in the area of ​​the end of the respective vertical guide surface furthest from the twin-disc spreader, so that the distributed material particles are first guided by the guide surfaces towards the central area of ​​the lane and then reflected obliquely downwards towards the ground at the central auxiliary guide surface.

[0038] Furthermore, it has proven advantageous if at least one through-opening, in particular the first through-opening, of a respective main guide surface of the boundary spreading device is assigned an impact surface, which is arranged on the opposing sides of a respective main guide surface and extends obliquely inwards and downwards from the upper end of the through-opening, in particular at an angle between 5° and 45°, preferably between 10° and 35°. In this way, the impact surface is able to reflect a portion of the material particles passing through the through-opening locally in the area of ​​this through-opening obliquely downwards towards the ground within the travel path of the twin-disc spreader.

[0039] The shape and size of the impact surface can essentially correspond to the shape and size of the cross-section of the at least one through-opening, whereby the respective impact surface can, for example, be cut out of the respective main guide surface and bent inwards.

[0040] According to an advantageous embodiment, to achieve an extremely uniform lateral distribution of the spreading material, it can further be provided that at least some of the guide surfaces of the boundary spreading device, such as, for example, at least the outer and / or the central auxiliary guide surfaces, are provided with a plurality of approximately wart-shaped, and in particular substantially uniformly distributed, protrusions. These substantially wart-shaped protrusions, which preferably extend approximately uniformly over the reflective surface of the respective guide surface, can, for example, have an approximately elongated, oval, or teardrop-shaped form and may also be provided with different base areas and / or heights in order to ensure a very uniform lateral distribution by reflecting material particles striking them in at least slightly different directions than material particles striking between the wart-shaped protrusions.

[0041] According to a further advantageous embodiment, it can be provided that each end section of a respective main guide surface of the boundary spreading device, facing away from the twin-disc spreader, is pivotable between its operating position and a transport and rest position, in which the end section of the respective main guide surface is folded out from the operating position. In this way, the boundary spreading device can be made more compact in its transport and rest position, so that it does not protrude excessively from the twin-disc spreader, especially during transport on public roads, and does not pose a danger to road traffic.

[0042] In its rest position, each end section of a respective main guide surface of the boundary scattering device can be folded outwards from the respective opposite main guide surface, in particular about a pivot axis extending essentially vertically parallel to the respective main guide surface.

[0043] Furthermore, the end sections of the main guide surfaces of the boundary spreading device can be mechanically, and in particular elastically, pre-loaded in the direction of their operating position, which can be achieved in particular by means of at least one spring acting between the end sections, such as a helical spring. In this way, it is ensured that the end sections of each main guide surface of the boundary spreading device are always held in their intended operating position during operation, while they can be moved into their transport and rest positions against their mechanical pre-load.

[0044] Finally, it proves advantageous, in a manner known to this effect, if the border spreading device is equipped with a lifting mechanism that serves to reposition the border spreading device between its operating position, in which it is essentially at the level of the distribution discs, and a transport and rest position, in which it is pivoted upwards away from the distribution discs. In this way, the border spreading device does not need to be mounted on the twin-disc spreader for border or edge spreading, but can remain on the twin-disc spreader during normal spreading and simply needs to be moved from its operating position to its transport and rest position using the lifting mechanism.

[0045] If a respective end section of a respective main guide surface can be pivoted between its operating position and a transport and rest position, in which the end section of the respective main guide surface is folded out from the operating position, as described above, the lifting device can preferably also, in particular by means of a lever rod, cooperate with a respective end section of a respective main guide surface of the border spreading device that can be pivoted between its operating position and its transport and rest position, in order to pivot the respective end section of a respective main guide surface between its operating position and its transport and rest position when moving the border spreading device between its operating position and its transport and rest position, so that no separate, in particular manual, intervention is required for this purpose.

[0046] 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 twin-disc spreader with a boundary spreading device in its operating position; Fig. 2 a schematic rear view of the twin-disc spreader equipped with the boundary spreading device in its operating position according to the Fig. 1 ; Fig. 3, essentially the Fig. 1 Fig. 4 shows a schematic side view of the twin-disc spreader with the boundary spreading device in its transport and rest positions; Fig. 4 shows a schematic rear view of the twin-disc spreader equipped with the boundary spreading device in its transport and rest positions according to the Fig. 3Fig. 5 a schematic perspective view of an embodiment of a boundary scattering device viewed from an oblique angle above; Fig. 6 a schematic perspective view of the boundary scattering device according to the Fig. 5 Viewed from a low angle; Fig. 7 a schematic perspective view of the border scattering device according to the Figs. 5 and 6 Viewed from a rear oblique angle; Fig. 8 a schematic top view of the border scattering device according to the Figs. 5 to 7 from above; and Fig. 9 a schematic top view of the border spreading device according to the Figs. 5 to 8 from underneath.

[0047] The one in the Figs. 1 to 4The depicted twin-disc spreader for agricultural purposes has a container 2 supported by a frame 1, which serves to store powdered or particulate material, such as fertilizer or seed. In this case, the container 2 comprises two container sections 2a and 2b that taper downwards in an approximately funnel-like shape, each having a discharge opening at its lower end (not visible in the drawings). Immediately below each discharge opening of the lower container sections 2a and 2b is a metering device (also not visible in the drawings), which is known from the prior art and is, for example,Each metering element comprises a metering slide that interacts with a respective discharge opening, wherein the metering slides of the two metering elements are preferably independently controllable and / or adjustable in order to set a mass flow of material corresponding to the respective target spreading quantity. Below each metering element, a distribution disc 3a, 3b is rotatably mounted about an approximately vertical axis A1, A2, wherein the distribution discs 3a, 3b are equipped with throwing vanes 4 in the usual manner. The distribution discs 3a, 3b are driven in opposite directions by means of suitable drives, wherein the drives can be, for example, electric or hydraulic motors (not shown), preferably with independently variable speed control. In the present case, the twin-disc spreader is designed as an attachment, the frame 1 of which is mounted on its... Fig. 1 and 3The left side includes a fastening device 5 which can be used to mount the twin-disc spreader by means of the three-point linkage of a tractor (not shown).

[0048] On its side opposite the fastening device 5, the twin-disc spreader is equipped with a joint bearing the reference numeral 10 and described below with reference to the Figs. 5 to 9 equipped with a border scattering device, which is explained in detail in the illustrations of the Figs. 1 and 2 in its operating position, in which it interacts with the distribution disc 3a, 3b opposite a field edge to ensure border or edge spreading (the metering element of the distribution disc 3b, 3a near the field edge is switched off in this case), whereas the border spreading device is shown in the illustrations of the Figs. 3 and 4in its transport and rest position, in which it is arranged, for example, at a level above the distribution discs 3a, 3b and does not come into contact with the material particles dropped by the distribution discs 3a, 3b in order to ensure normal spreading in the field interior.

[0049] How especially the Figs. 5 to 9 As can be seen, the information in the Figs. 1 and 2In its operating position, the boundary spreading device 10 has two essentially vertically arranged main guide surfaces 11, which diverge symmetrically to the longitudinal axis of the twin-disc spreader from a point P 1 located between the distributor discs 3a, 3b (here: approximately in the central area between the axes of rotation A1, A1 of the distributor discs 3a, 3b) obliquely outwards and – viewed in the longitudinal direction of the twin-disc spreader – away from the distributor discs 3a, 3b. Each main guide surface 11 of the boundary spreading device 10 extends obliquely outwards to a point P 2 and – viewed in the longitudinal direction of the twin-disc spreader – away from a respective distributor disc 3a, 3b, whose imaginary horizontal connecting line L 1 (cf. the Fig. 9The angle α of at most approximately 30° is formed between the axis of rotation A 2 of the respective distributor disc 3b and an imaginary horizontal line L 2 intersecting the respective axis of rotation A 2 of the respective distributor disc 3b and extending in the longitudinal direction of the twin-disc spreader, where the angle α is approximately 6° in the present case. In the illustrated embodiment, the main guide surfaces 11 of the boundary spreading device 10 therefore extend obliquely outwards and away from the twin-disc spreader by almost a quarter of the circumference of each respective distributor disc 3a, 3b.

[0050] The main guide surfaces 11 of the boundary spreading device 10 have, on the one hand, a section 11a close to the twin-disc spreader, which extends, for example, over approximately 20% to 30% of the total length of each main guide surface 11, wherein the angle formed between the sections 11a of the main guide surfaces 11 is less than approximately 15° and, in the present case, approximately 0°, i.e., the sections 11a of the main guide surfaces 11 close to the twin-disc spreader are arranged approximately parallel to each other. On the other hand, the main guide surfaces 11 of the boundary spreading device 10 have a section 11b farther from the twin-disc spreader, which extends, for example, over approximately 30% to approximately 50% of the total length of each main guide surface 11, wherein the angle formed between the sections 11b of the main guide surfaces 11 is between approximately 80° and approximately 130° and, in the present case, approximately 104°, i.e.,The sections 11b of the main guide surfaces 11 furthest from the twin-disc spreader diverge at a maximum angle relative to the other sections of the main guide surfaces 11. In addition, the main guide surfaces 11 of the boundary spreading device 10 in the present case have a first central section 11c adjoining their section 11a closest to the twin-disc spreader, the length of which is, for example, similar to that of the sections 11a or somewhat greater, wherein the angle formed between the first central sections 11c is between about 10° and about 30° and in the present case about 18°.Finally, in the present case, the main guide surfaces 11 of the boundary spreading device 10 have a second central section 11d extending outwards and rearwards from the first central section 11c, which extends, for example, over approximately 5% to approximately 15% of the total length of each main guide surface 11, with the angle formed between the second central sections 11d being between approximately 25° and approximately 65°, and in the present case approximately 45°. The angle formed between the two main guide surfaces 11 of the boundary spreading device 10 thus increases successively in several stages from the sections 11a closest to the twin-disc spreader, through the central sections 11c and 11d, to the sections 11b furthest from the twin-disc spreader.

[0051] A cover guide surface 12 adjoins each main guide surface 11 of the boundary spreading device 10 at its upper end, i.e., at its upper edge. This cover guide surface 12 extends obliquely outwards and upwards at an angle of approximately 90° to approximately 150°, and in the embodiment shown in the drawing, for example, at an angle of approximately 115° to approximately 120° with respect to the respective main guide surface 11. The width of each cover guide surface 12 increases, for example, from its end closest to the twin-disc spreader in the region of sections 11a of the main guide surfaces 11 towards its end furthest from the twin-disc spreader in the region of sections 11b of the main guide surfaces 11.

[0052] In the illustrated embodiment, several short outer auxiliary guide surfaces 13a, 13b, 13c are arranged on the opposite sides of the two main guide surfaces 11 of the boundary scattering device 10. These auxiliary guide surfaces are short compared to the total length of each main guide surface 11 and extend at an angle of approximately 30° to 60°, e.g., approximately 45°, relative to the main guide surfaces 11. Their length, considered in the direction of extension of the main guide surfaces 11, corresponds, for example, to approximately 5° to approximately 10° of the total length of each main guide surface 11. The outer auxiliary guide surfaces 13a, 13b, 13c extend obliquely upwards and outwards from the lower end of each main guide surface 11, with the end of each outer auxiliary guide surface 13a, 13b, 13c opposite the lower end of the main guide surface 11 being, for example,The guide surface is fixed to a respective cover guide surface 12 via a leg angled in the opposite direction. In the illustrated embodiment, an outer auxiliary guide surface 13a is arranged at the end furthest from the twin-disc spreader of each respective main guide surface 11, i.e., at the free end of the respective section 11b of the respective main guide surface 11 furthest from the twin-disc spreader. An outer auxiliary guide surface 13b is also arranged at the section 11b of each respective main guide surface 11 furthest from the twin-disc spreader, but at a distance from the end of the respective main guide surface 11 furthest from the twin-disc spreader, e.g., in the central region of the section 11b furthest from the twin-disc spreader.In addition, for example, an outer auxiliary guide surface 13c is arranged on a central section of a respective main guide surface 11 - here: in the area of ​​the end of the first central section 11c facing the second central section 11d.

[0053] As furthermore, particularly from the Figs. 5 to 9As can be seen, in the embodiment shown in the drawing, each main guide surface 11 of the boundary spreading device 10 has two through-openings 14, 15 arranged at least at a distance from the end of the respective main guide surface 11 furthest from the twin-disc spreader, which are arranged symmetrically with respect to the longitudinal axis of the twin-disc spreader or to that of the boundary spreading device. A first through-opening 14 of each main guide surface 11 is arranged in the region of the end of the first central section 11c facing the second central section 11d of the respective main guide surface 11, while a second through-opening 15 of each main guide surface 11 extends substantially over its second central section 11d into the end region of the section 11b furthest from the twin-disc spreader that faces and adjoins it (see the Figs. 5 and 6The through-openings 14, 15 are arranged, for example, close together in the direction of extension of a respective main guide surface 11, with a distance of only about one or a few centimeters. In this case, the opening cross-section of the first through-opening 14, which is closer to the twin-disc spreader, is smaller than that of the second through-opening 15, being, for example, about one-third to about half the opening cross-section of the second through-opening 15. In order to be able to change the distribution width within the track of the twin-disc spreader, both the opening cross-section and the position of the second through-opening 15 of a respective main guide surface 11 can be changed by means of a slide 16 guided on the respective main guide surface 11 in its direction of extension, which can at least partially close the second through-opening 15, as indicated by arrow P in the figure. Fig. 5 is indicated. While the slider 16 in the Fig. 5in a partially closed position, in which it closes a section of the second through-opening 15 furthest from the twin-disc spreader, it is shown in the illustration of the Fig. 6 in its open position, in which it practically exposes the entire opening cross-section of the second through-opening 15. If the slide 16 is in its open position according to the Fig. 5 , it is arranged at the end of the through-opening 15 furthest from the twin-disc spreader (in the Fig. 6 to the right of the same; not recognizable), while in its partially closed position of the Fig. 5a partial cross-section of the second passage opening 15, located away from the twin-disc spreader, is closed off. The slide 16 may also be assigned a scale (not shown) that identifies various partially closed positions and indicates, for example, the desired distribution width within the driving lane or, if necessary, also beyond the field edge on the side facing it, which corresponds to the respective opening position of the slide 16.

[0054] Each pair of both the first 14 and the second through-openings 15 of a respective main guide surface 11 of the boundary spreading device 10 is furthermore assigned a common central auxiliary guide surface 17, 18, which is arranged on the side of the respective pair of through-openings 14, 15 facing away from the twin-disc spreader and extends between the main guide surfaces 11 at an angle of, for example, approximately 45° with respect to a horizontal plane between the main guide surfaces 11 from one of the upper regions of the main guide surfaces 11 near the respective through-openings 14, 15 to one of the lower regions of the main guide surfaces 11 furthest from the respective through-openings 14, 15 (see in particular the Fig. 6The angle of inclination of the central auxiliary guide surfaces 17, 18 thus corresponds approximately to that of the outer auxiliary guide surfaces 13a, 13b, 13c, and the central auxiliary guide surfaces 11 also serve to reflect the spread material particles obliquely downwards towards the ground, but in the area of ​​the travel path of the twin-disc spreader. Furthermore, each pair of both the first 14 and the second through-openings 15 of a respective main guide surface 11 is assigned two vertical guide surfaces 19a, 19b, 20a, 20b converging towards the end of the boundary spreading device 10 facing away from the twin-disc spreader. These guide surfaces are arranged on the side of the pair of through-openings 14, 15 facing away from the twin-disc spreader and are fixed to the sides of the main guide surfaces 11 facing each other.The guide surfaces 19a, 19b, 20a, 20b serve to guide the spreading material particles, which have passed through a respective through-opening 14, 15, towards the center of the travel path of the twin-disc spreader, before they hit the respective central auxiliary guide surface 17, 18 arranged between the two respective guide surfaces 19a, 19b, 20a, 20b which converge towards the end of the boundary spreading device 10 facing away from the twin-disc spreader and are reflected from there obliquely downwards towards the ground.

[0055] Especially in the Figs. 5 and 6It is further evident that, in the present embodiment, each of the first through-openings 14 of a respective main guide surface 11 of the boundary spreading device 10 is assigned an impact surface 21, which is arranged on the opposing sides of each main guide surface 11 and extends obliquely inwards and downwards from the upper end of the first through-opening 14, e.g., at an angle of approximately 20°. The shape and size of the impact surfaces 21 correspond, e.g., essentially to the shape and size of the cross-section of the first through-openings 14, whereby the respective impact surface 21 can, for example, be cut out of the respective main guide surface 11 and bent inwards, and can serve to reflect the spreading material particles passing through the first through-opening 14 obliquely downwards towards the ground within the lane.

[0056] Furthermore, at least some of the guide surfaces of the boundary spreading device 10, such as in particular at least the outer auxiliary guide surfaces 13a, 13b, 13c and the central auxiliary guide surfaces 17, 18, can be provided with a plurality of approximately wart-shaped, in particular essentially uniformly distributed, elevations (not shown) in order to reflect the spreading material particles impacting them more broadly and in this way to achieve a particularly uniform lateral distribution both inside and outside the driving lane of the twin-disc spreader.

[0057] To place the border spreading device 10 in a transport and rest position (see the Figs. 3 and 4) to give it a higher degree of compactness, so that it does not protrude excessively from the twin-disc spreader, e.g. during transport on public roads, and does not pose a danger to road traffic, in the embodiment shown in the drawing, the rear end sections of each main guide surface 11 facing away from the twin-disc spreader – or more precisely: the end sections of sections 11b – are formed between their in the Fig. 1, 2 and 5 up to 9 reproduced operating positions and one in the Figs. 3 and 4 The transport and rest position shown, in which the end section of the respective main guide surface 11 is folded outwards from the operating position, is pivotable about an approximately vertical pivot axis S, as shown in the Fig. 7as indicated by the arrows V. In order to keep the end sections of the sections 11b of the main guide surfaces 11 in their operating position at all times during operation, the end sections are mechanically preloaded, in this case elastically by means of helical springs 22 acting between the end sections of the main guide surfaces 11, in the direction of their operating position.

[0058] To connect the border spreading device 10 between its in the Figs. 1 and 2 shown operating position, in which it is essentially arranged at the level of the distributor discs 3a, 3b, and its transport and rest position according to the Figs. 3 and 4 , in which it is pivoted upwards away from the distribution discs 3a, 3b, the boundary spreading device 10 is further equipped with a feature particularly in the Fig. 5 , 7 and 8equipped with a recognizable lifting device 30, by means of which it is fixed to the side of the twin-disc spreader opposite the fastening device 5. As in particular the Fig. 5 As can be seen, the lifting device 30 in the present case comprises two triangular levers 31, which are pivotably connected to the border spreading device 10 at one of their corners about an approximately horizontal axis X, while at another of their corners they are fixed to the twin-disc spreader by means of an equally approximately horizontal shaft Y, wherein the shaft Y - either manually or by motor - is moved into its transport and rest position for the purpose of raising the border spreading device 10 ( Figs. 1 and 2 ) or in order to lower them into their operating position ( Figs. 1 and 2 ) can be rotated back and forth (see also the Fig. 1 and 3). At the other corner of each triangular lever 31, one end of a lever rod 32 is pivotably attached about an approximately horizontal axis Z, the opposite end of which is attached to the end section of a respective main guide surface 11 which can be folded out about the vertical pivot axis S, such that when the boundary spreading device 10 is raised / lowered between its operating position and its transport and rest position, by rotating the shaft Y and pivoting the triangular levers 31 about their axis X, the end sections of a respective main guide surface 11 are simultaneously folded about their pivot axis S by means of the lever rods 32 in order to pivot them in turn between their operating position and their transport and rest position.

Claims

1. Twin-disc spreader having two distributor discs (3a, 3b) rotationally driven in opposite directions about parallel axes (A1, A2) and having a border spreading device (10), which in its operating position is arranged centrally between the distributor discs (3a, 3b) and has two main guide surfaces (11), which are arranged substantially vertically and which diverge symmetrically with respect to the longitudinal axis of the twin-disc spreader obliquely outwards, respectively, from a point (P1) arranged between the distributor discs (3a, 3b) and - viewed in the longitudinal direction of the twin-disc spreader - away from the distributor discs (3a, 3b), wherein - a respective main guide surface (11) of the border spreading device (10) extends obliquely outwards and - viewed in the longitudinal direction of the twin-disc spreader - away from a respective distributor disc (3a, 3b) up to a point (P2) each, the imaginary horizontal connecting line (L1) of which with the axis of rotation (A1, A2) of the respective distributor disc (3a, 3b) encloses an angle (α) of at most 30° with an imaginary horizontal line (L2) extending in the longitudinal direction of the twin-disc spreader and intersecting the respective axis of rotation (A1, A2) of the respective distributor disc (3a, 3b), and - a respective main guide surface (11) of the border spreading device (10) has at least one through opening (14, 15) arranged at a distance from the end of the respective main guide surface (11) that is furthest from the twin-disc spreader, which through openings are arranged symmetrically with respect to the longitudinal axis of the twin-disc spreader.

2. Twin-disc spreader according to claim 1, characterized in that a respective main guide surface (11) of the border spreading device (10) extends obliquely outwards up to a point (P2) each and - viewed in the longitudinal direction of the twin-disc spreader - away from a respective distributor disc (3a, 3b), the imaginary horizontal connecting line (L1) of which with the axis of rotation (A1, A2) of the respective distributor disc (3a, 3b) encloses an angle (α) of at most 20°, in particular of at most 10°, preferably between 2° and 10°, with an imaginary horizontal line (L2) extending in the longitudinal direction of the twin-disc spreader and intersecting the respective axis of rotation (A1, A2) of the respective distributor disc (3a, 3b).

3. Twin-disc spreader according to claim 1 or 2, characterized in that a cover guide surface (12) is attached to the upper end of a respective main guide surface (11) of the border spreading device (10), which cover guide surface (12) extends outwards with respect to the respective main guide surface (11), at an angle between 90° and 150°, in particular between 90° and 135°,wherein the width of a respective cover guide surface (12) increases in particular from its end nearest to the twin-disc spreader towards its end furthest from the twin-disc spreader.

4. Twin-disc spreader according to any of claims 1 to 2, characterized in that the angle formed between the two main guide surfaces (11) of the border spreading device (10) - increases from the end nearest to the twin-disc spreader towards the end furthest from the twin-disc spreader, in particular in multiple stages; and / or - at the portion (11a) nearest to the twin-disc spreader of the main guide surfaces (11), is less than 15°, in particular less than 10°, preferably less than 5°, wherein the two main guide surfaces (11) of the border spreading device (10) are arranged in particular in a substantially parallel manner at their portions (11a) nearest to the twin-disc spreader; and / or - at the portion (11b) furthest from the twin-disc spreader of the main guide surfaces (11), is between 80° and 130°, in particular between 90° and 120°, preferably between 100° and 110°, wherein the portions (11b) away from the twin-disc spreader of the two main guide surfaces (11) extend in particular over at least 30%, in particular over at least 35°, preferably over at least 40%, of the total length of a respective main guide surface (11).

5. Twin-disc spreader according to any of claims 1 to 4, characterized in that the main guide surfaces (11) of the border spreading device (10) between their portions (11a) near the twin-disc spreader and their portions (11b) away from the twin-disc spreader - each have at least one first central portion (11c) which are arranged at an angle to each other between 10° and 30°, in particular between 12° and 26°, preferably between 14° and 22°; and / or - each have at least one second central portion (11d) which are arranged at an angle to each other between 25° and 65°, in particular between 30° and 60°, preferably between 35° and 55°.

6. Twin-disc spreader according to any of claims 1 to 5, characterized in that on the sides facing away from each other of the two main guide surfaces (11) of the border spreading device (10), respectively at least one, in particular respectively at least two, short outer auxiliary guide surface (13a, 13b, 13c) is arranged opposite the total length of a respective main guide surface (11), which auxiliary guide surface (13a, 13b, 13c) extends obliquely upwards and outwards from the lower end of a respective main guide surface (11) at an angle between 30° and 60°, in particular between 35° and 55°, preferably between 40° and 50°, with respect to the respective main guide surface (11), in particular the length of the outer auxiliary guide surfaces (13a, 13b, 13c) - viewed in the direction of extension of the main guide surfaces (11) - respectively being at most 20%, in particular at most 15%, preferably between 5% and 10%, of the total length of a respective main guide surface (11).

7. Twin-disc spreader according to claim 6, characterized in that at least - one outer auxiliary guide surface (13a) eachare arranged at the end of a respective main guide surface (11) that is away from the twin-disc spreader; and / or - one outer auxiliary guide surface (13b) eachare arranged on the portion that is away from the twin-disc spreader (11b) of a respective main guide surface (11), which form the largest angle between them, but at a distance from the end of a respective main guide surface (11) that is away from the twin-disc spreader; and / or - one outer auxiliary guide surface (13c) each is arranged on at least one central portion (11c) of a respective main guide surface (11), which are arranged at an angle to each other between 10° and 65°, in particular between 10° and 30°, wherein in particular the respective outer auxiliary guide surface (13c) is arranged nearer to the end of a respective main guide surface (11) that is near to the twin-disc spreader than to its end that is away from the twin-disc spreader.

8. Twin-disc spreader according to any of claims 1 to 7, characterized in that a respective first through opening (14) of a respective main guide surface (11) of the border spreading device (10) is arranged on at least one central portion (11c) of a respective main guide surface (11), which are arranged at an angle to each other between 10° and 65°, in particular between 10° and 30°, the respective first through opening (14) being arranged in particular nearer the end of a respective main guide surface (11) that is nearto the twin-disc spreader than its end that is away from the twin-disc spreader.

9. Twin-disc spreader according to any of claims 1 to 8, characterized in that a second through opening (15) of a respective main guide surface (11) of the border spreading device (10) is arranged - on at least one central portion (11d) of a respective main guide surface (11), which are arranged at an angle to each other between 30° and 60°, and / or - on the portion (11b) of a respective main guide surface (11) that is away from the twin-disc spreader in the region of the end which is opposite to the free end of the portion (11b) of a respective main guide surface (11) that is away from the twin-disc spreader, wherein a respective second through opening (15) extends, in particular from the central portion (11d) of a respective main guide surface (11), which is adjacent to the portion (11b) of a respective main guide surface (11) that is away from the twin-disc spreader, to the region adjacent to this region of the portion (11b) of a respective main guide surface (11) that is away from the twin-disc spreader.

10. Twin-disc spreader according to any of claims 1 to 9, characterized in that the opening cross-section and / or the position of at least one through opening (14, 15), in particular of the second through opening (15), of a respective main guide surface (11) of the border spreading device (10) is changeable, wherein theat least one through opening (15) is at least partially closable, in particular by means of a slide (16) guided on the respective main guide surface (11), wherein the slide (16) is displaceable, in particular between an open position in which the slide is arranged at the end away from the twin-disc spreader of the through opening (15) , and an at least partially closed position in which the slide closes at least apartial cross-section away from the twin-disc spreader of the through opening (14, 15)..

11. Twin-disc spreader according to any of claims 1 to 10, characterized in that a respective main guide surface (11) of the border spreading device (10) has at least one first through opening (14) as well as at least one second through opening (15), whose distance - viewed in the direction of extension of a respective main guide surface (11) - is in particular at most 30 cm, in particular at most 20 cm, preferably at most 10 cm.

12. Twin-disc spreader according to any of claims 1 to 11, characterized in that at least one pair of the at least one through openings (14, 15), respectively, of a respective main guide surface (11) of the border spreading device (10) - is assigned to at least one common central auxiliary guide surface (17, 18), which is arranged on the side facing away from the twin-disc spreader of the respective pair of through openings (14, 15) and extends between the main guide surfaces (11) at an angle between 30° and 60°, in particular between 35° and 55°, preferably between 40° and 50°, with respect to a horizontal plane between the main guide surfaces (11) from an upper region of the main guide surfaces (11) that is near the respective through opening (14, 15) to a lower region of the main guide surfaces (11) that is away from the respective through opening (14, 15); and / or - is assigned to two vertical lead guide surfaces (19a, 19b; 20a, 20b) converging towards the end of the border spreading device (10) facing away from the twin-disc spreader, which lead guide surfaces are arranged between the two main guide surfaces (11) on the side of the respective pair of through openings (14, 15) facing away from the twin-disc spreader, wherein the at least one common central auxiliary guide surface (17, 18) is arranged in particular between the two vertical lead guide surfaces (19, 19b; 20a, 20b) converging towards the end of the border spreading device (10) facing away from the twin-disc spreader.

13. Twin-disc spreader according to any of claims 1 to 12, characterized in that a baffle (21) is assigned to at least one through opening (14) of a respective main guide surface (11) of the border spreading device (10), which baffle is arranged on the mutually facing sides of a respective main guide surface (11) and extends obliquely inwards and downwards from the upper end of the through opening (14), in particular at an angle between 5° and 45°, preferably between 10° and 35°, wherein the shape and size of the baffle (21) corresponding in particular substantially to the shape and size of the cross-section of the at least one through opening (14), and wherein the respective baffle (21) is in particular cut out of the respective main guide surface (11) and bent inwards.

14. Twin-disc spreader according to any of claims 1 to 13, characterized in that at least some of the guide surfaces (11, 12, 13a, 13b, 13c, 17, 18, 19a, 19b, 20a, 20b, 21) of the border spreading device (10) are provided with multiple approximately nodular, in particular substantially uniformly distributed, elevations.

15. Twin-disc spreader according to any of claims 1 to 14, characterized in that a respective end portion of a respective main guide surface (11) of the border spreading device (10), facing away from the twin-disc spreader, is pivotable between its operating position and a transport and rest position in which the end portion of the respective main guide surface (11) is folded out from the operating position, wherein a respective end portion of a respective main guide surface (11) of the border spreading device (10) in particular - in its rest position, in particular about a pivot axis (S) that extends substantially vertically and parallel to the respective main guide surface (11), being folded outwards away from the respective opposite main guide surface (11); and / or - being mechanically, in particular elastically, preloaded in the direction of its operating position, in particular by means of at least one spring (22) acting between the end portions.

16. Twin-disc spreader according to any of claims 1 to 15, characterized in that the border spreading device (10) is equipped with a lifting device (30) which serves to relocate the border spreading device between its operating position, in which it is substantially arranged at the level of the distributor discs (3a, 3b), and a transport and rest position, in which it is pivoted upwards away from the distributor discs (3a, 3b), wherein the lifting device (30) in particular further, in particular by means of a lever rod (32), interacting with a respective end portion of a respective main guide surface (11) of the border spreading device (10) that is pivotable between its operating position and its transport and rest position, in order to pivot the respective end portion of a respective main guide surface (11) between its operating position and its transport and rest position while relocating the border spreading device (10) between its operating position and its transport and rest position.