GB2088682A - Reversible plough - Google Patents

Abstract

A tractor-mounted reversible plough has a plough frame (15) which is pivoted with the aid of a turning cylinder (5) from the one working position into the other. At the same time the plough end is lifted by means of a pivot cylinder (14) so far that an adequate clearance remains between plough end and ground. For this purpose the turning cylinder (5) is formed as a hydraulic cylinder which can change over automatically in the The pivot cylinder (14) is connected to the hydraulic conduits (6) of the turning cylinder (5) and thus chargeable simultaneously with the latter. Due to the collaboration of the two cylinders (5, 14), favoured by a quantity divider arranged in the pressure conduit (8) or a constriction (9), the turning operation proceeds continuously. The pivoting in of the plough frame (15) and the turning operation advantageously overlap one another <IMAGE>

Description

SPECIFICATION Reversible plough The invention relates to a reversible plough having a hydraulic turning cylinder engaging with the swivel and the plough turret and having a pivoting device for raising the plough frame end.

In the known mounted reversible ploughs, the plough frame is pivoted by means of the turning cylinder over the swivel from the one working position into the other. In order to obtain an adequate clearance between plough end and ground in the half-turned position in multi-furrow mounted reversible ploughs, attempts have been made to raise the plough end as far as possible. A reversible plough is known (German Pub. Sp. 23 60 739) in which in turning the plough end is lifted by means of a pivot device formed as a hinged rod which is connected indirectly with the plough front frame. In this case it is disadvantageous that the turning cylinder must supply the full turning energy especially in the initial positions in order to move the plough frame.

This is due to the fact that at the beginning and at the end of the turning movement the pivot point has the maximum lever arm in each case. It is also disadvantageous that the hinged rod in the case of shifts of inclination influences other previously effected settings, as for example the furrow width of the first plough body. Therefore a time-consuming correction of the other settings is necessary each time.

To avoid the mentioned disadvantages it has been proposed (German Utility Model 77 26 689) to provide such a mounted reversible plough with a device for pivoting the plough frame which is actuatable independently of the turning cylinder and is operated through valves in such a way that the pivot spindle is blocked in the reversing of the plough frame.

In such a mounted reversible plough the plough frame is firstly pivoted in by means of the pivot cylinder, before the actual turning operation commences, in order then to remain in this position during the turning operation.

Then after the conclusion of the turning operation the plough frame is automatically pivoted back again into the intended initial position. Apart from the fact that additional expenditure of time and, due to corresponding valve equipment, a considerable regulating cost are neccessary, the turning operation itself cannot proceed continuously, since the turning cylinder must be changed over by the tractor driver at the dead point. Thus the progress of the turning operation is substantially dependent upon the skill of the driver, since if the change-over occurs at the wrong moment considerable damage occurs to the plough and the hydraulics. A further essential advantage is to be seen in that the plough frame is automatically pivoted back after termination of the turn. Thus the advantageously reduced turning or tilting moment cannot be retained during travel on the headlands.Specifically in the case of multi-furrow mounted reversible ploughs, for which this pivoting device is of special importance, the turning or tilting moments are very great and make themselves especially conspicuous in turning and reversing on slopes.

The invention is therefore based upon the problem, with a continuous turning operation of the plough frame and low expense for regulation, of guaranteeing an adequate ground clearance of the plough frame end and of reducing the loadings occurring due to the turning and tilting moments, even in travel on the headland.

According to the invention the problem is solved in that the turning is formed as a hydraulic cylinder which is chargeable over automatically in the dead point region and the pivot device is formed as a hydraulic pivot cylinder which is connected to the hydraulic conduits of the turning cylinder and thus chargeable simultaneously.

Due to the collaboration of the automatically changing hydraulic cylinder and the simultaneously chargeable pivot cylinder, the entire turning operation can proceed continuously and the pivoting-in of the plough frame and the turning operation overlap one another. The plough frame is here lifted with its end so that the ground clearance necessary for the turning operation is guaranteed in each case. The pivoting-in here begins at the beginning of turning and ends at the latest when the half-turned position is reached. As a side effect here a saving of energy occurs due to the fact that the centre of gravity is placed substantially closer to the swivel, so that the turning and tilting moments are minimised at the same time. The stability of tractor and plough is increased, which proves beneficial especially on slopes.After the second working position of the plough frame is reached and the turning operation is terminated, and expediently only after the return journey on the headland, the plough frame is pivoted back, namely by a separate actuation.

A division of the oil flow to the turning cylinder and the pivot cylinder is ensured in accordance with the invention in that in the pressure conduit a quantity divider is arranged in the branch or a constriction is arranged behind the branch to the turning cylinder.

The pivot cylinder, which is to be used at the same time for the adjustment of the furrow width of the foremost plough body, according to a development of the invention comprises an adjustable retraction limiter to pressure the furrow width of the foremost plough body once set. Such a retraction limiter is expediently a known adjusting nut which permits retraction of the cylinder only as far as the point determined by the adjusting nut.

Arresting of the pivot cylinder in the case of interruption of the turning operation or at the "neutral" setting is achieved in that with the pivot cylinder there is associated a shut-off valve acting in both directions, which closes if the oil flow is interrupted.

According to an especially expedient form of embodiment of the invention it is provided that the pivot cylinder is part of a quadrilateral linkage formed together with the plough frame, the plough front frame and the main link, the angle of which linkage is adjustable by means of a diagonal link of variable length.

In such an apparatus it is advantageously possible to combine the transmission for the adjustment of the width and of the ideal tractor towing point with the apparatus for the optimalisation of the turning operation. Thus a tractor-mounted reversible plough is produced in which all the adjusting and regulating devices essential to the working of the reversible plough are brought together at one position so that they are easily accessible and can be handled well.

The invention is distinguished especially in that the necessary ground clearance of the plough frame end is ensured without making the turning operation itself longer or more difficult. Furthermore only a simple constriction or a guantity divider, which minimise the regulating expense, are necessary for the turning operation including pivoting in and back.

It is especially advantageous that the operation of pivoting in of the plough frame is integrated into the turning operation, so that the entire procedure can take place continuously. Due to the lifting of the plough frame end and thus also the shift of the centre of gravity into the line of action of the swivel, the turning and tilting moments during the turning operation itself and during driving on the headland are advantageously kept so small that the stability of the tractor is guaranteed even in the case od extremely unfavourn- ble terrain.

Further details and advantages of the object of the invention appear from the following description of the accompanying drawing, in which a preferred example of embodiment is represented with the necessary details and individual parts and wherein: Figure 1 shows a lateral elevation of the mounted reversible plough with plough frame half turned and with supply conduits.

The tractor carrying the mounted half-turn plough is not represented. The connection between tractor and plough is constituted through what is called the three-point linkage, the plough front frame 1, 2 comprising the necessary attachment points for the links of the three-point linkage. The swivel 3 is mounted in the usual way in the transverse beam 1. The swivel 3 comprises a laterally protruding arm 4.

The turning cylinder 5, which is supplied with the necessary hydraulic fluid through the hydraulic conduits 6, acts upon the plough turret 2 and the swivel 3. The turning cylinder 5 is one which switches over automatically in the dead point region, so that merely by this the handling of the mounted half-turn plough is substantially facilitated. The hydraulic conduits 6 consist of return conduit 7 and pressure conduit 8. A constriction 9 is connected into the pressure conduit 8 so that the pivot cylinder 14 with its conduit departing from the branch 11 is charged with pressure fluid at the same time. Likewise a quantity divider can be arranged in the branch 11.

The pivot cylinder 14 forms a part of the quadrilateral linkage 10. This quadrilateral linkage 10 is further formed from the main link 1 2 and the arms 4 and 1 8. This quadrilateral linkage 10 serves to connect the plough front frame 1, 2 with the plough frame 15, which carries several plough bodies 16, 1 7. The diagonal link 13, by means of which the ideal tractor towing point is adjusted in order to avoid sideways pull upon the tractor (not shown) and thus to maintain steerability of the tractor, engages with the arm 4 and the main link 12.

To the pivot cylinder 14 or its piston rod there is allocated an adjusting nut by means of which the furrow width of the foremost plough body 1 6 can be set according to the requirements in each case. This adjusting nut, serving as retraction limiter 20 determines the point to which the piston rod of the pivot cylinder 14 can be retracted. Furthermore with the pivot cylinder 14 there is associated a shut-off valve 21 which closes in both directions if the oil flow is interrupted, so that the pivot cylinder 14 remains arrested in this position.

When the headland is reached, in the case of the apparatus according to the invention the tractor driver needs only to charge the turning cylinder 5 with pressure, that is to say to set its working valve appropriately. Simultaneously with the charging of the turning cylinder 5 and the commencement of the turning operation, the pivot cylinder 14 receives pressure fluid and pushes out. Thus the plough frame 15, as illustrated in chain-line form in Fig. 1, is pivoted in as far as possible so that the centre of gravity of the plough frame approaches the line of action of the swivel 3.

Thus the end of the plough frame 1 5 gains adequate ground clearance. By means of the constriction 9 it is ensured that the pivot cylinder 14 and the turning cylinder 5 are charged simultaneously and come into action simultaneously. The pivot cylinder 14 pushes out more quickly, so that the plough frame 1 5 is pivoted in fully at the latest before the halfturned position as shown in Fig. 1 is reached.

The turning operation then proceeds continu ously even beyond the dead point, and is automatically terminated only after the end position is reached. By actuation of his control valve the tractor driver than ensures that the pivot cylinder 14 pivots the plough frame 1 5 back into its initial position. The retraction limiter 20 here ensures that the plough can pivot back only as far as the set position.

Correction of the other adjusting elements is not necessary.

Claims (6)

1. A reversible plough having a hydraulic turning cylinder acting upon the swivel and upon the plough turret and having a pivot for lifting the plough frame end, wherein the turning cylinder is formed as a hydraulic cylinder capable of changing over automatically in the dead point region and the pivot device is formed as a hydraulic pivot cylinder connected to the hydraulic conduits of the turning cylinder and thus chargeable at the same time.

2. A plough as claimed in claim 1, wherein in the pressure conduit a quantity divider is arranged in the branch or a constriction is arranged behind the branch to the turning cylinder.

3. A plough as claimed in claim 1 or 2, wherein the pivot cylinder comprises an adjustable retraction limiter to preserve the set furrow width of the foremost plough body.

4. A plough as claimed in claim 1 or 2, wherein with the pivot cylinder there is associated a shut-off valve acting in both directions which closes if the oil flow is interrupted.

5. A plough as claimed in claim 4, wherein the pivot cylinder is part of a quadrilateral linkage formed together with the plough frame, the plough front frame and the main link, the angle of which linkage is adjustable by means of a diagonal link of variable length.

6. A reversible plough substantially as described herein with reference to the accompanying drawings.