Patent GB-598056-A (GB)
Title: Improvements in or relating to hitch means for connecting a tractor with an implement or the like
IPC: A01B59/042
Filed: 1944-09-04
Abstract: 598,056. Adjusting agricultural implements. FERGUSON, Inc., H. Sept. 4, 1944, No. 16848. Convention date, Nov. 10, 1943. [Class 6 (i)] [Also in Group XXXII] A coupling between a tractor 10 and harrow 11 comprises an upper link 28 and a pair of lower links 29 pivoted to the tractor at one end and connected by a lever 34 at the other, and drag links 49, adapted to raise the links to their collapsed position in Fig. 4, whereby the free end of the lever 34 moves forwardly to operate a slide 25 on the harrow draw-bar 23 to align the gangs to the travelling position. The links 29 are connected by a transverse bar 32 to the centre of which the lever 34 is fixed and also the draw-gear links 35 which are connected to an upstanding bar 37 hinged between plates 39 on the harrow draw-bar 23 and movable between stops therein for ease in coupling. The lower end of lever 34 is provided with a shoe 48 which protects its connection with a link 46 attached to the slide 25 and also functions to operate the hydraulic ram if the shoe strikes the ground. The upper link 28 is adjustable in length and is pivoted to one arm of a T-shaped lever pivoted by its stem to the tractor casing, the other arm of the lever being connected to a ram reversal control member 15. A spring 16 surrounds the member 15 and opposes the thrust of the link 28 for all normal thrusts due to movement of the coupling, but is overcome when the shoe strikes the ground or the tractor drops into a depression to operate the ram and raise the links. The ram may be operated by the driver through a hand lever 14 to raise the links, the return of the links being controlled by the release of pressure, the down or towing position of the links being limited by a chain 53 adjustable in notches 54 on the link 28. In Fig. 1, the harrows 20, 21 are shown in their working position, the harrows 20 being pivoted about midway of their length to bars 22 which are attached at their other ends to the draw-bar 23, the sliding bar 25 being connected to the inner ends of the harrows by rods 26 whereby movement of the sliding bar towards the tractor brings the harrows into alignment for travelling. Pivoted links 27, 24 connected to the harrows 21 and draw-bar 23 respectively, align the rear gang simultaneously. When the rear wheels of the tractor moves into a depression, the draught connection causes a relative upward swing of the linkage and the movement of the upper link 28 swings the upper end of the lever 34 rearwardly to exert a forward pull on the slide 25 to draw the harrows into a less angled position. The same result occurs when the shoe 48 strikes the ground. In these movements the thrust on the link 28 is not sufficient to overcome the compression of the spring 16 and the link merely swings about its pivot on the T-shaped lever 18, but should the link 28 be subjected to excessive compression, due to the sudden lowering of the end of the tractor, the spring 16 is overcome and the plunger moved inwardly to admit pressure fluid to operate the ram and raise the arms 12 and lift the linkage. The linkage will rise until the compressive force on the upper link is relieved and the plunger 15 returned to its neutral position. The draught on the linkage will then tend to return it to the normal position.