Straddling Tractors

The present invention relates to an improvement in straddling tractors, that is to say, tractors whose front and rear wheels are disposed at the end of legs so that they will be raised high enough to be able to straddle a row of vines.

The use of this kind of tractor, originally reserved exclusively to viniculture, tends to extend to other agricultural activities, in particular for the cultivation of corn and cereals, up to the time of their maturity, that is to say when the vegetation is at maximum height.

The use of these raised tractors now presents problems in the hitching of the cultivation implements to the raising means which are sometimes too high.

It is the object of the present invention to provide a solution to this type of problem, and it relates to a hitching device designed in such a way as to permit the hitching on the ground of the equipment ordinarily used in agriculture.

By way of example, and to facilitate comprehension of the invention, there is represented, in the attached drawings:

In FIG. 1, a side elevation in partial section of a first embodiment of a tractor according to the invention;

In FIG. 2, a partial, three-quarter rear view in perspective, of the tractor of FIG. 1;

In FIG. 3, a detail view of an alternative of FIG. 3;

In FIG. 4, a partial side view, in section, of a second embodiment;

In FIG. 5, a view corresponding to FIG. 4;

In FIG. 6, a side elevation in partial section, of an alternative embodiment of the tractor of FIG. 1.

Referring to these figures, and more particularly to FIG. 1, we note that the chassis of the tractor has a platform 1, borne by front legs 2 and rear legs 3 equipped with front wheels 4 and rear wheels 5. Preferably, the legs 2 and 3 on the same side, are connected together by a reinforcing brace 6.

The drive assembly, that is to say motor 7 and gearbox 8, are located on the platform 1 in such a way that the center of gravity of this assembly will be substantially in the center of the suspension polygon defined by the four wheels.

It is quite clear that if there is mounted on platform 1, the usual hitching links of tractors, it will not be possible to hitch thereto, implements which are on the ground. It is necessary either to have a lifting means available, or to first put the implement to be hitched onto a trestle having approximately the height of platform 1.

In French Pat. No. 2,337,985 in the name of the applicant, there is a proposal for a solution which includes disposing the articulation of the lifting links in practically the median plane of the tractor, giving them sufficient length and disposing the power takeoff in this same median plane. This solution is satisfactory, but exhibits several drawbacks, in particular with regard to the rigidity of these hitching links, which are quite long.

According to the invention, the straddling tractor has, at the rear, a gantry 11, along which a second gantry 12 can slide, the latter bearing means of attachment of a conventional 3-point hitch. Preferably, and as represented in FIG. 2, the first gantry 11 is an inverted U-shaped frame with two vertical side uprights 13 connected by an upper cross-piece 14, the assembly being reinforced by stays 15. Inside the lateral uprights 13 there are rails 13a. The lateral uprights can, for this purpose, be formed by U-profiles forming rails.

Inside the rails 13a, there slides the second gantry 12, which is likewise formed by a frame with two lateral uprights 16 connected by an upper crosspiece 17 and reinforced by stays 18. Each upright 16 has, at its base, a cap 19 in which there is placed a sliding piece 20 bearing a hitching journal 21. Preferably, each sliding piece 20 can slide in cap 19, and can be fixed in any desired position by a clamping means 22.

The upper crosspiece 17 has in its center, a stirrup 23, bearing the upper hitching link 24 and its journal 25. The sliding movement of gantry 12 in gantry 11 can be obtained by any known mechanical means. In the example represented, it is obtained by means of two symmetrical jacks 26, fixed on the one hand to gantry 11 and on the other hand to gantry 12. It is seen, then, that by means of jacks 26, gantry 12 can be lowered to the level of the hitching axes of the implement which is on the ground, so that it will be possible to place these axes in the two lower journals 21 and in the upper journal 25. After this the gantry 12 is raised by jacks 26, which raises the implement and brings it to the desired height.

This two-gantry lifting system can be disposed on any type of tractor, but in the event it is disposed on a tractor such as the one described in FIG. 1, it is particularly advantageous to articulate gantry 11 on the rear legs 3 about aligned horizontal axes 27. This, as a matter of fact, makes it possible to tilt gantry 11 forward, bringing the center of gravity of the tool closer to the center of gravity of the tractor.

In FIG. 1, the tilted position 11' of the gantry is illustrated diagrammatically in dotted lines, as well as position 21' and 25' of the hitching journals. This is extremely advantageous for improving the equilibrium and the stability of the tractor-implement assembly. The tilting of gantry 11 can be obtained either by means of stays 40 fixed in several positions on horizontal arms 41 by means of a plurality of holes 42, as in FIG. 1 or by means of one or more hydraulic jacks 43, as in FIG. 2. In the latter case the intermediate shaft 28 or power takeoff jack shaft must be telescopic, which is already known.

When the gantry 12 is to be tilted, it is usually necessary to have means allowing the implement to be in a horizontal position. For this purpose, as shown in FIG. 2, there is disposed on link 24, a plurality of holes 24a, by means of which the said link 24 is fixed to stirrup 23. In more advantageous fashion, link 24 can be replaced with a jack 24b, FIG. 3, whose shaft, at its end, bears journal 25. This permits control of the attitude of the tool from the driver's seat of the tractor.

FIGS. 4 and 5 represent an alternative embodiment in which the same elements bear the same reference numbers. Referring to this figure it is seen that gantry 12 includes a triangular armature 29, pivotally connected to said gantry 12 about a horizontal axis 30. This triangular armature has a vertical arm 31 and two lower arms 32. Each of the arms 32 bears a cap 19, which, as described above, bears sliding piece 20, journal 21 and clamping means 22. The upper link 24, bearing journal 25, is pivotally connected to armature 29. Vertical arm 31 is pivotally connected to the end of the shaft of a jack 33 which is borne by a support 34 connected to gantry 11.

Thus, when gantry 11 is tilted by means of jacks 43 into the position represented in FIG. 5, armature 29 can pivot around axis 30, by means of jack 33 in such a way that the implement, represented diagrammatically by the two dashed lines 35, remains parallel to itself.

According to another alternative embodiment, armature 29 can also serve as a support for a hydraulic, electric or pneumatic motor 36, driving a fluted shaft 37 analogous to the power takeoff shaft 38, the hydraulic motor in the example represented being fed by hoses 39.

The various jacks are controlled by a control device 44.

It is also possible that the reactions of the implements hitched to link 24 will be, as on a conventional farm tractor, utilized to act on the height of sliding frame 12 by means of jacks 26.

FIG. 6 represents an alternative embodiment of the tractor of FIG. 1. According to this alternative, the tractor has, in the front, a lifting device identical to the one in the rear. This rear lifting device is formed by a gantry 11b (identical to gantry 11) in which there slides a second gantry 12b (identical to gantry 12). Gantry 12b bears two caps 19b in which is placed a sliding piece 20b bearing a hitching journal 21b, as well as a stirrup 23b bearing an upper hitching link 24b and journal 25b. The movement of gantry 12b relative to gantry 11b is produced by jacks 26b. A power takeoff jack shaft 28b is also provided, this shaft being driven by a supplementary gearbox 45 located in front of motor 7.

Gantry 11b is carried by two lateral tabs 46, mounted rotatably on an axis 47, borne by one or more brackets 48. Circular slots 49 permit the adjustment of the inclination of gantry 11b.