Abstract: A process of setting the length of an upper steering arm of an attaching device of a tractor. The attaching device includes the upper steering arm with a power drive provided for length setting purposes; a length sensor to determine the actual length of the upper steering arm; two lower steering arms with a lifting mechanism to lift and lower the lower steering arm; a lift sensor to determine the actual position of lift of the steering unit; as well as a control unit. The nominal lengths of the upper steering arm (7), to be determined as a function of the directions of movement of the lifting mechanism, are stored in the control unit. Determining the actual length of the upper steering arm (7), the actual position of lift of the lifting mechanism and the direction of movement of the lifting mechanism.

Abstract: A coupling hook (5) for a lower steering arm of a tractor (1) has a hook body (7) with a bearing recess (8) to receive a bearing ball (6) of a to be coupled implement. The hook body has a recess (9), a through hole (10) between the recess (9) and the bearing recess (8), an exiting aperture (11) connecting to the recess (9) and open to the exterior, and a first support element (12) and a second support element (13). The second support element (13) extends through the exiting aperture (11) and separates the exiting aperture into a first opening portion (14) and a second opening portion (15). A locking pawl (17) is movable between a locking position, where it projects into the bearing recess (8), and a detaching position, where it is retracted into the through hole (10). An adjustment element (30) engages the locking pawl (17) and acts on it to take up the locking position. An opening lever (26) is pivotably connected to the locking pawl (17) and is movably supported on the second support element (13).

Abstract: A process of setting the length of an upper steering arm of an attaching device of a tractor. The attaching device includes the upper steering arm with a power drive provided for length setting purposes; a length sensor to determine the actual length of the upper steering arm; two lower steering arms with a lifting mechanism to lift and lower the lower steering arm; a lift sensor to determine the actual position of lift of the steering unit; as well as a control unit. The nominal lengths of the upper steering arm (7), to be determined as a function of the directions of movement of the lifting mechanism, are stored in the control unit. Determining the actual length of the upper steering arm (7), the actual position of lift of the lifting mechanism and the direction of movement of the lifting mechanism.

Abstract: A linear adjustment element, which can be extended along a longitudinal axis between a shortened retracted position and a moved out position, has a first connection element 1, a second connection element 8, and a hose-like expansion element 22. The hose-like extension element 22 can be elastically elongated and is air-tight and liquid-tight. The hose-like expansion element 22 is connected in a sealed manner at its first end portion 23 to the first connection element 1 and at its second end portion 24 to the second connection element 8. The hose-like expansion element 22 has an outer face 25. A pressure chamber 29, delimited by the connection elements 1, 8and the expansion element 22, can be pressurised and depressurised via a tube element 6. A support element 26 is arranged around the outer face 25 of the expansion element 22.

Abstract: A coupling for coupling, for example, a trailer having a drawbar (2) to a tractor with a three-point linkage device, which has two height-adjustable lower steering arms (3, 4) of which one is laterally adjustable by a lateral strut (11). A first coupling element is mounted on the rear of the tractor. The drawbar (2) is provided with a second coupling element (13). The second coupling element (13) is connectable to the first coupling element (12). The coupling has a bar 14 with two ends. Each end includes a connection element (15) to connect with the lower steering arms (3, 4) of the tractor (1). A guiding mechanism comprises two guiding pins is arranged, distanced from each other, on the bar (14). The guiding bar (14) supports the drawbar (2). The drawbar (2) is guided between the guiding pins (17). The drawbar (2) is adjustable relative to the bar (14) in the longitudinal direction.

Abstract: A coupling for coupling, for example, a trailer having a drawbar (2) to a tractor with a three-point linkage device, which has two height-adjustable lower steering arms (3, 4) of which one is laterally adjustable by a lateral strut (11). A first coupling element is mounted on the rear of the tractor. The drawbar (2) is provided with a second coupling element (13). The second coupling element (13) is connectable to the first coupling element (12). The coupling has a bar 14 with two ends. Each end includes a connection element (15) to connect with the lower steering arms (3, 4) of the tractor (1). A guiding mechanism comprises two guiding pins is arranged, distanced from each other, on the bar (14). The guiding bar (14) supports the drawbar (2). The drawbar (2) is guided between the guiding pins (17). The drawbar (2) is adjustable relative to the bar (14) in the longitudinal direction.