Coupling arrangement for an agricultural tractor

Abstract

A coupling arrangement (10) for an agricultural tractor (12) comprises a drawbar (16) with a first rod section (24) which is mounted in a holder (28) for attachment to an underside (40) of a power take-off shaft housing (42) of the agricultural tractor (12) so as to be longitudinally displaceable along a predetermined adjustment range, and a second rod section (26) opposite the first rod section (24), which is guided within adjacent upper and lower support cheeks (44, 46) of a coupling carrier plate (52) and can be fixed therein by means of a securing element (22) in one of several coupling positions along the predetermined adjustment range.It is provided that the pull rod (16) is designed, at least along the predetermined adjustment range, as a double-T profile (54) running upright within the holder (28) with upper and lower flanges (58, 60) connected by a web (56), wherein left and right inner projections (62, 64) on the holder (28) are positioned on both sides of the web (56) of the double-T profile (54) in such a way that a lateral guide of the pull rod (16) is formed within the holder (28).

Description

The invention relates to a coupling arrangement for an agricultural tractor, comprising a drawbar having a first rod section which is mounted in a holder for attachment to an underside of a power take-off gear housing of the agricultural tractor such that it can be displaced longitudinally along a predetermined adjustment range, and a second rod section which is situated opposite the first rod section and is guided within adjacent upper and lower support cheeks of a coupling carrier plate and can be fixed therein by means of a securing element in one of a plurality of coupling positions along the predetermined adjustment range.Such a clutch arrangement is known, for example, in agricultural tractors from the manufacturer John Deere. This comprises a pull rod having a first rod section and a second rod section opposite the first rod section. The first rod portion is supported in a bracket on the underside of a differential housing of the agricultural tractor and is secured therein by a removable pin extending through a bore formed in the first rod portion and bolted to the differential housing. Furthermore, the second rod section has left and right threaded bores in the region of an end plate carrying a coupling ball for receiving associated hex bolts, by means of which the end plate is screwed to a coupling carrier plate provided in the rear region of the agricultural tractor. The tie rod can be mounted in one of two different coupling positions by releasing the stud and the two hexagonal bolts, so that different operating situations of an attachment attached to the coupling ball can be taken into account.Due to the construction, the vertical forces occurring during operation of the attachment on the tie rod directly act on the screw connection produced by means of the two hexagonal bolts, so that correspondingly high tightening torques are required here. These have the result that a movement of the tie rod between the two clutch positions is possible only with correspondingly high outlay and generally remains reserved for a workshop stay.In order to facilitate handling when moving the pull rod, it is therefore proposed in DE 10 2023 104 695 A1 to guide the second rod section within adjoining upper and lower support cheeks of a clutch carrier plate provided for rear attachment to the agricultural tractor. In this case, the pull rod can be moved into a plurality of coupling positions by longitudinal displacement and can be locked therein with respect to the coupling carrier plate by means of at least one securing element. The guidance of the pull rod in the region of the second rod section by means of the two support cheeks or upper and lower sliding surfaces formed thereon ensures that the vertical forces occurring on the pull rod during operation of the attachment can be introduced directly into the coupling carrier plate. These are therefore no longer associated with the actuating forces to be applied to the at least one securing element for locking the tie rod, so that the latter can be preset as desired with regard to comfortable handling of the tie rod when changing between its different coupling positions by appropriate selection or structural design of the at least one securing element.On this basis, it is the object of the present invention to further optimize a clutch arrangement of the type mentioned at the beginning with regard to its handling.This object is achieved by a clutch arrangement having the features of claim 1.The coupling arrangement for an agricultural tractor comprises a drawbar having a first rod section which is mounted in a holder for attachment to an underside of a power take-off gear housing of the agricultural tractor such that it can be displaced longitudinally along a predetermined adjustment range, and a second rod section which is situated opposite the first rod section and is guided within adjacent upper and lower support cheeks of a coupling carrier plate and can be fixed therein by means of a securing element in one of a plurality of coupling positions along the predetermined adjustment range. According to the invention, it is provided that the pull rod is formed at least along the predefined adjustment range as an I-profile or double-T-profile running upright within the holder with upper and lower flanges connected by a web, wherein left and right cheeks or inner projections are positioned or end on the holder on both sides of the web of the double-T-profile in such a way that a lateral guidance of the pull rod is formed within the holder.The use of a double-T profile leads, in comparison with solid cross-sectional shapes, such as those which have a rectangular profile made of solid material, not only to increased rigidity but also to a corresponding weight reduction of the tie rod, which reduces the material costs as well as further facilitates the handling thereof.By means of the securing element, the tie rod can be locked within the coupling carrier plate horizontally in both the longitudinal and transverse directions with respect to the installation position on the agricultural tractor. The vertical support of the tie rod is effected substantially by means of the upper and lower support cheeks of the coupling carrier plate adjoining the second rod section. When used on the agricultural tractor, laterally directed traction force components occur in the area of the mounting, which are introduced into the mounting and from there into the power take-off shaft transmission housing because of the lateral guidance of the traction rod realized by means of the cheeks or inner projections.Advantageous further developments of the clutch arrangement according to the invention are evident from the dependent claims.Preferably, the adjustment region is continued as far as the open end of the first rod section, so that the pull rod can be completely pulled out of the holder. This makes it possible to remove the tie rod completely from the coupling arrangement in the event of its non-use or a replacement due to maintenance without dismantling the holder.In order to ensure the most uniform possible introduction of the vertical forces occurring on the drawbar as a result of operation into the support structures of the agricultural tractor adjoining the holder or coupling carrier plate, it is also possible that, in order to form a sliding guide along the predefined adjustment range, a flat running surface is provided on an outer side of the upper and / or lower flange for bearing against an underside of the power take-off shaft gear housing or a flat counter surface on the holder.The at least one securing element is, for example, a threadless securing bolt which, for locking the tie rod, is guided through mutually aligned positioning openings formed in the coupling carrier plate and the second rod section and is secured therein by means of a splint or the like.On the securing bolt, which is typically provided with a handle, a circumferential collar is formed in particular, which, in the mounted state, is supported on an upper side of the coupling carrier plate and is fixed thereon by means of a rotation prevention means, so that maintenance of a defined operating position of the handle is ensured. The anti-rotation means can be formed, for example, by a flattened portion provided on the encircling upper collar, on which flattened portion a stop provided on the upper side of the clutch carrier plate engages.It can also be provided that left and right runners are formed on the coupling carrier plate for accommodation in a rail system carrier of a tractor coupling system. The rail system carrier typically takes the form of a hanger mounted on a differential housing in the rear region of the agricultural tractor. The hanger bracket comprises left and right latching rails into which the runners of the coupling carrier plate are inserted and screwed by means of a plurality of threaded bolts.To the second rod portion, a coupling member equipped with, for example, a ball head may be attached. Usually, this is a so-called K80 ball head, which serves for the attachment of a complementary ball socket of an attachment coupling. The ball head can be detachably mounted on the second rod section or the coupling element for the purposes of replacement due to maintenance or wear.Furthermore, left and right pocket-shaped recesses can be provided on the second rod section, which recesses are designed to produce a releasable dovetail connection with left and right additional coupling elements for actuating a positive steering included in a steerable attachment. Each of the additional coupling elements carries a K50 ball, into which a steering actuation linkage of the positive steering can be suspended. To secure the dovetail connection, each of the two additional coupling elements is additionally firmly screwed to the second rod section. The steerable attachment can be, for example, a transport trailer or a garbage cane.The clutch arrangement according to the invention for an agricultural tractor is described in more detail below with reference to the drawings. Identical reference numerals refer to components that correspond or are comparable in function. The following are shown: FIG. 1 is an exploded perspective view of an embodiment of the clutch assembly for an agricultural tractor according to the invention, FIG. 2 is an illustration of the coupling arrangement shown in FIG. 1 in the assembled state, FIG. 3 is a side view, in section, of the clutch arrangement shown in FIG. 2 on a power take-off shaft gear housing of the agricultural tractor in a first clutch position, FIG. 4 is a side view, shown in section, of the clutch arrangement shown in FIG. 2 on a power take-off shaft gear housing of the agricultural tractor in a second clutch position, FIG. 5 shows the coupling arrangement shown in FIG. 2, completed with left and right additional coupling elements attached thereto for actuating a positive steering included in a steerable attachment, and FIG. 6 shows the completed clutch arrangement shown in FIG. 5 viewed from below.FIGS. 1 and 2 show various perspectively illustrated complete views of an exemplary embodiment of the clutch arrangement 10 according to the invention for an agricultural tractor 12 (indicated merely in the drawing) in an exploded illustration and in the assembled state.The coupling arrangement 10 located in the rear region 14 of the agricultural tractor 12 comprises a pull rod 16 which can be moved longitudinally into different coupling positions 18, 20 and can be fixed therein by means of a securing element 22 (see FIGS. 3 and 4 in this regard).More specifically, the pull rod 16 made of steel forging includes a first rod portion 24 and a second rod portion 26 opposed to the first rod portion 24. The first rod section 24 is mounted in a holder 28 so as to be longitudinally displaceable along a predetermined or permissible adjustment range ΔL.As can be seen in particular in FIG. 1 in conjunction with FIGS. 3 and 4, the holder 28 comprises a support plate 32 which extends transversely with respect to the longitudinal extent 30 of the drawbar 16 and extends in the form of a bridge between two mounting portions 34, 36 and is screwed by means of a plurality of threaded bolts 38 on an underside 40 of a power take-off gear housing 42 of the agricultural tractor 12. The second rod section 26 is guided largely without play within adjoining upper and lower support cheeks 44, 46 or upper and lower sliding surfaces 48, 50 of a clutch carrier plate 52 formed thereon.The tie rod 16 is designed, at least along the predefined or permissible adjustment range ΔL, as an I-profile or double-T-profile 54 which extends upright within the holder 28 and has upper and lower flanges 58, 60 connected by a web 56. Left and right cheeks or inner projections 62, 64 on the holder 28 are positioned on both sides of the web 56 of the double T-profile 54 in such a way that a lateral guidance of the tie rod 16 is formed within the holder 28. For this purpose, the cheeks or inner projections 62, 64 formed integrally on the mounting portions 34, 36 of the holder 28 end in the region of sliding surfaces 66, 68 formed thereon at the smallest possible distance from a running surface 70, 72 provided on a respectively adjoining outer side of the web 56.In the present case, the adjustment range ΔL is continued as far as the open end 74 of the first rod section 24, so that the pull rod 16 can be completely pulled out of the holder 28. This allows the pull rod 16 to be completely removed from the coupling arrangement 10 in the event of its non-use or service-related replacement without dismantling the holder 28.Furthermore, left and right runners 76, 78 are formed on the clutch carrier plate 52 for receiving in a rail system carrier 80 of a tractor clutch system 82. The rail system carrier 80 has the form of a hanger bracket 84 mounted on the power take-off shaft transmission housing 42 in the rear region 14 of the agricultural tractor 12 (cf. FIGS. 3 and 4 ). The hanger bracket 84 comprises left and right grid rails 86, 88, into which the runners 76, 78 of the coupling carrier plate 52 are inserted and screwed by means of a plurality of threaded bolts 90 a, 90 b.As can be seen from the sectional representations of the coupling arrangement 10 in FIGS. 3 and 4, the pull rod 16 can be moved into one of the coupling positions 18, 20 by longitudinal displacement and can be locked therein with respect to the coupling carrier plate 52 by means of the securing element 22. According to the example, two coupling positions 18, 20 are provided, but it can also be any other number with optionally deviating rastering.By means of the securing element 22, the pull rod 16 is locked horizontally both in the longitudinal and transverse direction within the coupling carrier plate 52 with respect to the installation position on the agricultural tractor 12. The vertical support of the tie rod 16 is effected substantially by means of the upper and lower support cheeks 44, 46 of the clutch carrier plate 52 adjoining the second rod section 26. In the region of the mounting 28, when used on the agricultural tractor 12, there occur primarily laterally directed tractive force components which are introduced into the mounting 28 and from there into the power take-off gearbox housing 42 on account of the lateral guidance of the tie rod 16 realized by means of the cheeks or inner projections 62, 64.In order to ensure the most uniform possible introduction of the vertical forces occurring on the drawbar 16 as a result of operation into the support structures of the agricultural tractor 12 adjacent to the holder 28 or clutch carrier plate 52, a flat running surface 92, 94 is provided for bearing against a flat counter surface 96, 98 on the underside 40 of the power take-off gear housing 42 or the holder 28, in order to form a sliding guide along the predefined or permissible adjustment range ΔL on an outer side of the upper and / or lower flange 58, 60.In the present case, the securing element 22 is a threadless securing bolt 100 which, for locking the tie rod 16, can be passed through aligned positioning openings 102, 104, 106, 108 formed in the coupling carrier plate 52 and the second rod section 26 and can be secured therein by means of a splint (not shown). The positioning openings 102, 104, 106, 108 run substantially perpendicular to the longitudinal extent 30 of the pull rod 16, wherein a plurality of positioning openings 106, 108 are provided spaced apart along the second rod section 26 corresponding to the respectively associated coupling position 18, 20 of the pull rod 16.On the securing bolt 100 provided with a handle 110, a circumferential collar 112 is formed, which in the mounted state is supported on an upper side 114 of the coupling carrier plate 52 and is fixed thereon by means of a rotation lock 116, so that maintenance of a defined operating position of the handle 110 is ensured. The anti-rotation device 116 is formed, for example, by a flattened portion 118 provided on the encircling upper collar 112, on which flattened portion a stop 120 provided on the upper side 114 of the clutch carrier plate 52 engages.Further, a coupling element 124 equipped with a ball head 122 is attached to the second rod portion 26 (see, among other things, FIG. 1 ). In the present case, this is a so-called K80 ball head which serves for the attachment of a complementary ball socket (not shown) of an attachment coupling. The ball head 122 is detachably mounted on the second rod portion 26 and the coupling member 124, respectively, for the purposes of maintenance replacement.Furthermore, left and right pocket-shaped recesses 126, 128 are provided on the second rod section 26, which recesses are designed to produce a releasable dovetail connection with left and right additional coupling elements 130, 132 for actuating a positive steering system comprised by a steerable attachment (not shown). This completed state is shown in FIG. 5. Accordingly, each of the additional coupling elements 130, 132 carries a K50 ball, into which a steering actuation linkage of the positive steering system can be suspended. To secure the dovetail connection, each of the two additional coupling elements 130, 132 is additionally firmly screwed to the second rod section 26 by means of a plurality of threaded bolts 134. The steerable attachment is, for example, a transport trailer or a garbage barrel. FIG. 6 thus shows the clutch arrangement 10 from below.For the sake of completeness, it should be noted that directional or course information used in the present context relates in each case to the installation position provided for operating the clutch arrangement 10 on the agricultural tractor 12.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2023 104 695 A1

[0004]

Claims

Coupling arrangement for an agricultural tractor, comprising a drawbar (16) having a first rod section (24) which is mounted in a holder (28) for attachment to a lower side (40) of a power take-off gear housing (42) of the agricultural tractor (12) such that it can be displaced longitudinally along a predetermined adjustment range, and a second rod section (26) which is situated opposite the first rod section (24) and is guided within adjacent upper and lower support cheeks (44, 46) of a coupling carrier plate (52) and can be fixed therein by means of a securing element (22) in one of a plurality of coupling positions (18, 20) along the predetermined adjustment range, characterized in that the drawbar (16) is designed at least along the predetermined adjustment range as a double-T profile (54) which runs upright within the holder (28) and has upper and lower flanges (58, 60) connected by a web (56), wherein left and right inner projections (62, 64) on the holder (28) are positioned on both sides of the web (56) of the double-T profile (54) such that a lateral guide of the tie rod (16) is formed within the holder (28).Clutch arrangement according to Claim 1, characterized in that the adjustment region is continued as far as the open end (74) of the first rod section (24).Clutch arrangement according to Claim 1 or 2, characterized in that, in order to form a sliding guide along the predefined adjustment range, a planar running surface (92, 94) is provided on an outer side of the upper and / or lower flange (58, 60) for bearing against an underside (40) of the power take-off shaft transmission housing (42) or a planar counter-surface (96, 98) on the holder (28).Coupling device according to at least one of the preceding claims, characterized in that the at least one securing element (22) is a threadless securing bolt (100), which is passed through aligned positioning openings (102, 104, 106, 108) formed in the coupling carrier plate (52) and the second rod section (26) in order to retain the tie rod (16).Coupling device according to Claim 4, characterized in that a circumferential collar (112) is formed on the securing bolt (100), which collar, in the mounted state, is supported on an upper side (114) of the coupling carrier plate (52) and is fixed thereon by means of a rotation prevention means (116).Coupling device according to at least one of the preceding claims, characterized in that left and right runners (76, 78) are formed on the coupling carrier plate (52) for receiving in a rail system carrier (80) of a tractor coupling system (82).Coupling device according to at least one of the preceding claims, characterized in that a coupling element (124) is attached to the second rod section (26).Coupling device according to at least one of the preceding claims, characterized in that left and right pocket-shaped recesses (126, 128) are provided on the second rod section (26), which recesses are designed for producing a releasable dovetail connection with left and right additional coupling elements (130, 132) for actuating a positive steering included in a steerable attachment.

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