Arrangement for the height-adjustable mounting of a trailer hitch on an agricultural vehicle

Abstract

Arrangement for the height-adjustable mounting of a trailer coupling on an agricultural vehicle, in particular an agricultural tractor, with two parallel, vertically extending guide rails (12), and with sliding rails (14) mounted longitudinally displaceable within the guide rails (12) and lockable by means of an associated locking device (44), wherein each of the sliding rails (14) has a longitudinally extending guide groove (16) for receiving a height-adjustable coupling element (18).

Description

The invention relates to an arrangement for the height-adjustable attachment of a trailer coupling to an agricultural vehicle, in particular an agricultural tractor. Such an arrangement for the height-adjustable mounting of a trailer coupling on an agricultural tractor is known, for example, from DE 10 2009 001 252 A1. This arrangement comprises two opposing guide rails extending vertically, which are rigidly mounted in the rear area of ​​the agricultural tractor. A bridge-shaped coupling support for attaching a drawbar runs between the guide rails, and the height of this bridge-shaped coupling support can be adjusted along the guide rails after releasing an associated locking mechanism. The adjustment range of the bridge-like coupling carrier is ultimately determined by the length of the guide rails used. The permissible length, in turn, results from requirements regarding ground clearance to be maintained during field work and the unobstructed access to fittings located in the upper rear section of the agricultural tractor, such as hydraulic or compressed air connections. This leads to corresponding limitations regarding the positioning options of the height-adjustable trailer coupling relative to the drawbar to be attached to it. It is therefore an object of the present invention to create an arrangement of the aforementioned devices with an improved adjustment range. This problem is solved by an arrangement for the height-adjustable mounting of a trailer coupling on an agricultural vehicle with the features of claim 1. The arrangement according to the invention comprises two vertically extending guide rails arranged parallel to each other, as well as sliding rails which are longitudinally displaceable within the guide rails and can be locked by means of an associated locking device, wherein each of the sliding rails has a longitudinally extending guide groove for receiving a height-adjustable coupling element. The coupling element is, for example, a bridge-like coupling support that is an integral part of the height-adjustable trailer coupling. The bridge-like coupling support, which extends into corresponding sliding skids on opposite sides, is positively engaged in the guide grooves of the sliding rails and is mounted therein so that it can be moved longitudinally for height adjustment. A locking mechanism secures the bridge-like coupling support within the sliding rails, and this locking mechanism can be released by means of a handle located on the upper side of the bridge-like coupling support. Since the sliding rails are mounted to be longitudinally displaceable within the two guide rails, they can be "telescopically" extended out of the guide rails and locked in this position by means of the locking device, thus allowing the coupling element to be positioned above or below the guide rails. The resulting arrangement therefore offers a greater adjustment range compared to conventional arrangements. The agricultural vehicle in question is, in particular, an agricultural tractor. In such a case, a power take-off (PTO) connection for attaching a driveshaft of an agricultural implement is typically located between the two guide rails. By positioning the coupling element above or below the guide rails, improved clearance is created for a driveshaft connected to the PTO connection. Advantageous embodiments of the arrangement according to the invention are set forth in the dependent claims. Depending on the requirements for the positioning accuracy of the coupling element, the slide rails can be locked either in stages or continuously using the locking device. For the stepwise locking of the slide rails, the locking device can have a removable locking bolt in the form of a plug pin or the like, which, in the assembled state, extends through a locking opening formed in one of the two guide rails in such a way that, while fixing the associated slide rail, it engages in a bolt receiving opening aligned with the locking opening of a plurality of bolt receiving openings provided along the slide rail. The bolt receiving openings, which are usually arranged equidistantly, open into the guide groove on the inside of the slide rail and simultaneously serve to engage a locking bolt encompassed by the locking mechanism of the coupling element, by means of which the coupling element can be fixed along the slide rail at the desired height. Preferably, the locking device has an identification feature that allows the locking bolt to be inserted only into predetermined bolt receiving openings, so that it can be ruled out that the slide rails can be locked in a position that is extended too far. For this purpose, the relevant bolt receiving openings can be designed as stepped bores, with these having a section on the side of the slide rail facing the locking bolt, into which the locking bolt can be inserted in a form-fitting manner. The remaining bolt receiving openings are designed as through bores with a constant bore diameter, so that the locking bolt can engage in them, but not the safety bolt. In order to achieve a refined, graduated locking of the slide rails, a first and second locking opening can be provided along the guide rail for the selective reception of the locking bolt, wherein the distance between the two locking openings differs from a multiple of the distance between equidistant bolt receiving openings, so that by repositioning the locking bolt between the two locking openings, a stepwise positioning of the coupling element in fractions of the distance between the bolt receiving openings is ultimately possible. Additionally, the locking bolt can be equipped with a locking element that prevents the locking bolt from unintentionally loosening from the locking opening due to vibrations or similar causes during driving. This locking element is, for example, a leg formed on the locking bolt with an opening through which, when the locking bolt is installed, a pin protruding from the guide rail extends. The leg can be secured to this pin by means of a removable spring ring. Alternatively, the locking device for stepless locking of the slide rails can have a clamping mechanism by means of which a friction element formed on one of the slide rails can be clamped against a complementary friction element formed within the associated guide rail. In the simplest case, the clamping mechanism is a screw bolt guided in the guide rail, the end of which can be clamped against the slide rail in such a way that a frictional connection is established between the two friction elements, thus preventing displacement. To prevent the sliding rails from falling laterally out of the guide rails in the absence of the bridge-shaped coupling support, the sliding rails can be supported on their mutually facing sides by means of undercuts running along the guide rails. The two guide rails are usually – as are the sliding rails – cast and / or forged parts made from a suitable steel alloy, on the inside of which several bearing seats or jaws are formed, which may be machined to achieve precise guidance of the sliding rails. The arrangement according to the invention is explained in more detail below with reference to the accompanying drawings. Components that are identical or comparable in function are marked with the same reference numerals. Figure 1 shows a semi-transparent embodiment of the arrangement according to the invention for the height-adjustable mounting of a trailer coupling on an agricultural vehicle, and Figure 2 shows a perspective view of a guide rail encompassed by the arrangement according to the invention as shown in Figure 1. Fig. 1 shows an embodiment of the arrangement according to the invention for the height-adjustable attachment of a trailer coupling to an agricultural vehicle (not shown), for example an agricultural tractor. The arrangement 10 comprises two guide rails 12 running parallel to each other and sliding rails 14 mounted longitudinally displaceable within the two guide rails 12, each of the sliding rails 14 having a longitudinally extending guide groove 16 for receiving a height-adjustable coupling element 18. The coupling element 18 is a bridge-like coupling support 20, which is an integral part of the height-adjustable trailer coupling 22. In this case, the bridge-like coupling support 20 includes a coupling jaw 24 for attaching a drawbar (not shown) of an agricultural implement, in particular a loading wagon. The bridge-like coupling support 20, which extends into corresponding skids 26 on opposite sides, is positively engaged in the guide grooves 16 of the slide rails 14 and is mounted therein so as to be longitudinally displaceable for the purpose of height adjustment. A locking mechanism 28 serves to secure the bridge-like coupling support 20 within the slide rails 14, and the locking mechanism 28 can be released by means of a handle 32 located on a top surface 30 of the bridge-like coupling support 20. To prevent the slide rails 14 from falling laterally out of the guide rails 12 in the absence of the bridge-shaped coupling support 20, the two slide rails 14 are mounted on their facing sides by means of undercuts 34 extending along the guide rails 12. For further details regarding the design of the undercuts 34, please refer to Fig. 2, which shows one of the two guide rails 12 in a perspective view. The two guide rails 12, like the sliding rails 14, are cast and / or forged parts made of a suitable steel alloy. As shown in Fig. 2, several bearing seats or bearing jaws 36 are formed on the inside of the guide rails 12, which are machined to achieve precise guidance of the respective sliding rail 14. Several mounting projections 38 formed on the guide rail 12, with mounting openings 40 formed therein, serve for screw fastening to a differential housing located in the rear area of ​​the agricultural tractor. The mounting openings 40 formed in the mounting projections 38 can be protected from the ingress of unwanted contaminants by attaching corresponding covers 42 (see Fig. 1). The slide rails 14 can be locked in stages within the guide rails 12 by means of a locking device 44. For this purpose, the locking device 44 has a removable locking bolt 46 in the form of a plug-in bolt for each of the two guide rails 12, which, in its assembled state, extends through a locking opening 48 formed in the respective guide rail 12 such that it engages, thereby securing the associated slide rail 14, in a bolt receiving opening 50 aligned with the locking opening 48 of a plurality of bolt receiving openings 50 provided along the slide rail 14.More precisely, first and second locking openings 48 are provided for the selective reception of the locking bolt 46, wherein the distance between the two locking openings 48 is in the present case 4.5 times the distance between the equidistantly arranged bolt receiving openings 50, so that by repositioning the locking bolt 46 between the two locking openings 48 a stepwise positioning of the bridge-like coupling carrier 20 in multiples of half the distance between the bolt receiving openings 50 is ultimately possible. The bolt receiving openings 50 open into the guide groove 16 on the inside of the respective slide rail 14 and simultaneously serve to engage a locking bolt 52 encompassed by the locking mechanism 28 of the coupling element 18, by means of which the bridge-shaped coupling carrier 20 can be fixed at the desired height along the slide rail 14. For clarity, the bridge-shaped coupling carrier 20 is shown in different positions in Fig. 1. Since the slide rails 14 are mounted to be longitudinally displaceable within the two guide rails 12, they can be "telescoped" into a position extended from the guide rails 12 and locked in this position by means of the locking device 44. This is illustrated in Fig. 1 by way of example in the case where the slide rails 14 are in an upwardly extended position and the bridge-shaped coupling carrier 20 is simultaneously in its uppermost position along the slide rails 14 and thus above the guide rails 12. Corresponding considerations apply to the case (not shown) where the slide rails 14 are in a downwardly extended position, in which the bridge-shaped coupling carrier 20 is in its lowermost position along the slide rails 14 and thus below the guide rails 12. The locking device 44 has an identification feature that allows the locking bolt 46 to be inserted only into predetermined bolt receiving openings 50, so that it can be ruled out that the slide rails 14 can be locked in a position that is extended too far. For this purpose, the relevant bolt receiving openings 50 are designed as stepped bores 54, wherein these have a section with a widened bore diameter on the side of the slide rail 14 facing the locking bolt 46, into which the locking bolt 46 can be inserted in a form-fitting manner. The remaining bolt receiving openings 50 are designed as through bores 56 with a constant bore diameter, so that the locking bolt 52 can engage in them, but not the locking bolt 46. Additionally, the locking bolt 46 is provided with a locking element 58, which prevents the locking bolt 46 from unintentionally loosening from the respective locking opening 48 due to vibrations or similar causes during driving. The locking element 58 is a leg 60 formed on the locking bolt 46 with an opening 62. When the locking bolt 46 is installed, a pin 64 projecting from the respective guide rail 12 extends through this opening, and the leg 60 can be secured to the pin 64 by means of a removable spring ring 66.

Claims

Arrangement for the height-adjustable mounting of a trailer coupling on an agricultural vehicle, in particular an agricultural tractor, with two parallel, vertically extending guide rails (12), and with sliding rails (14) mounted longitudinally displaceable within the guide rails (12) and lockable by means of an associated locking device (44), wherein each of the sliding rails (14) has a longitudinally extending guide groove (16) for receiving a height-adjustable coupling element (18). Arrangement according to claim 1, characterized in that the slide rails (14) can be locked in stages or continuously by means of the locking device (44). Arrangement according to claim 2, characterized in that the locking device (44) for stepwise locking of the slide rails (14) has a removable locking bolt (46) which, in the assembled state, extends through a locking opening (48) formed in one of the guide rails (12) in such a way that it engages, while fixing the associated slide rail (14), in a bolt receiving opening (50) aligned with the locking opening (48) of a plurality of bolt receiving openings (50) provided along the slide rail (14). Arrangement according to claim 3, characterized in that the locking device (44) has an identification feature that allows the locking bolt (46) to be inserted exclusively into predetermined bolt receiving openings (50). Arrangement according to claim 3 or 4, characterized in that a first and second locking opening (48) for selectively receiving the locking bolt (46) is provided along the guide rail (12), wherein the distance between the two locking openings (48) differs from each other by a multiple of the distance between equidistant bolt receiving openings (50). Arrangement according to one of claims 3 to 5, characterized in that the locking bolt (46) is provided with a locking element (58) by means of which an unwanted release of the locking bolt (46) from the locking opening (48) can be prevented. Arrangement according to one of claims 1 to 6, characterized in that the two sliding rails (14) are mounted on mutually facing sides by means of undercuts (34) extending along the guide rails (12).

Images