PLOUGH

Abstract: This invention relates to a plough preferably a reversible plough comprising a frame and at least one plough beam applied at the frame to support one or preferably several plough bodies. The plough beam is supported at the frame (10) by means of a three point connection in such a way that the plough beam when being released turns about a first connecting point (at 14) at the same time as the cooperating parts of a second conneting point (at 15) are released from each other or viceversa and that the third connection point comprises a joint (23) which is movable with respect to the frame for adjusting the width of the ridge.

Description: This invention relates to a plough preferably a reversible plough having a frame with at least one beam supporting one or preferably several plough bodies. Ploughs of the above type are usually equiped with so called safety release devices in order to prevent the plough from being damaged when hitting obstacles in the ground. These safety release devices usually are so designed that each beam is pivotally fastened to a beam support which is attached to the frame and the beam is pressed downwards by means of a spring, a hydraulic cylinder being connected to a gasaccumulator or the like. When hitting an obstacle the beam pivots vertically or obliquely upwards and when the obstacle has been passed the beam is again forced back into the ground by the spring or the cylinder. An embodiment of a reversible plough which exists on the market is for instance provided with a beam having two upper and two lower bearing points arranged in a square pattern, the bearing points being open bearing cups with which spherical bearing surfaces cooperate. The bearing cups might be parts of a beam support attached to the frame whereas the spherical bearing surfaces might be parts of the plough beam, the bearing cups and bearing surfaces being pressed towards each other by means of a spring device. When hitting an obstacle the plough beam pivots about a connecting line between the two upper bearing points and at the same time the bearing cups and the spherical bearing surfaces at the lower bearing points are released from each other. When the frame of the reversible plough is turned 180° in order to make it possible to change the ploug direction a later pivoting movement of the plough beam will be accomplished about the connecting line between those points which previously was the lower but in the new position are the upper bearing points. In order to make it possible to adjust the width of the ridge for this type of ploughs each plough beam support has to be loosend and turned about a vertical axis after which it is locked in a new position. This work is extensive and time consuming and the arrangement does not give a possibility to make a continious adjustment. It also means that the design is relatively complicated with separate systems for releasing the beam and for adjusting the width of the ridge. The purpose of this invention is to create a simple and reliable arrangement where the above functions are integrated into one unit and also having the advantage that all plough beams can be adjusted in common. The invention will now be described with reference to the accompanying drawings in which Fig. 1 is a schematic perspective view showing a frame with a plough beam, Fig. 2 is a side view of a modified arrangement and Fig. 3 is a plan view of the last mentioned arrangement. In Fig. 1 10 is a frame, supporting several T-shaped plough beams 11. Each plough beam is provided with a right hand laying and a left hand laying plough body not shown. The plough frame 10 has a beam fastening support 12 for each plough beam the support being attached to the frame by bolts 13 and being provided with an upper and a lower bracket 14 and 15 which are welded to the support. Each bracket has a threaded hole through which a bolt 16 is inserted and locked by a nut. The head 17 of the bolt 16 which faces the front part of the beam is spherical and cooperates with an upper and a lower cup shaped bearing surface 18 and 19 respectively on the plough beam in order to form two of the points in a three point connection for the plough beam. The plough beam is further provided with a dowel 20 which in the working position of the plough extends horisontally sideways through a hole 21 in a waist part 22 of the frame, the dowel 20 being secured to the beam between the two cup shaped bearing surfaces 18 and 19 and somewhat behind a line connecting theses two bearing surfaces with each other. In its outer end the dowel 20 is inserted into a pivot joint 23 which is a part of a guide bar 24. The guide bar 24 is by means, not shown, movable forwards and backwards in the length direction of the frame 10. A release cylinder 25, being in hydraulic connection with a gas accumulator, not shown, and operating as a compression spring, is linked to a mandrel 26 which is welded to the frame 10. The piston rod of the cylinder is via a link joint 27 turnably and swingably secured to the dowel 20. By means of the cylinder, the piston acts on the dowel 20 so that the beam is pressed towards the heads 17 of the bolts 16. The device operates in the following way. When the frame is moved to the right in fig. 1 and the plough body hits an obstacle the plough beam 11 will pivot upwards about a line connecting the upper bearing point, which is the point were the bearing surface 18 abuts the head 17 of the bolt 16, with the pivot joint 23. This means that the cup shaped bearing surface 19 will go out of engagement with the head of the bolt at the lower bracket 15. The cylinder 25 is simultaneously moved by the dowel 20 so that the cylinder pivots about the mandrel 26 as well as the link joint 27 at the same time as the piston of the cylinder tries to reset the plough beam to its original position. When the obstacle has been passed the plough beam 11 will then return to its normal working position and the cup shaped bearings surface 19 will again engage the head of the bolt at the lower bracket 15. In its second working position, that is when the plough frame has been turned through 180°, the bearing point which is defined by the cup shaped bearing surface 19 and the head of the bolt at the corresponding bracket 15 will be placed at the top which means that any turning of the plough now will take place about this point. When the width of the ridge has to be adjusted this will occur simultaneously for all plough beams by moving the guide bar 24 in the length direction of the frame. This is preferably done hydraulicly or manually. Thus, the pivot joint 23 is moved forwards or backwards which means that the plough beam is turned about a vertical axis connecting the two bearing points which are defined by the cup shaped bearing surfaces 18, 19 and the heads 17 of the bolts 16 with each other. This in turn means that the distances between the plough bodies and the frame is increased or decreased in a corresponding way. Movement forwards of the guide bar 24 causes a smaller width of the ridge whereas movement of the joint towards the rear gives a larger width of the ridge. It should be observed that it is possible to make small adjustments of the position of the bearing points with respect to the frame by means of adjusting the bolts 16. It is of course possible to exchange positions between the cup shaped bearing surfaces and the spherical bearing surfaces of the head of the bolts as well as to use other types of devices in the connecting points. It is also possible to use a tensioning means instead of the pressure cylinder operating between the frame and the beam as well as it is possible to place the force creating means between the guide bar and the dowel or plough beam. By placing the pivot joint and the dowel at a suitable distance behind the axis connecting the two bearing points with each other it is possible to achieve a decreasing force curve when the device is released which is desirable this being achieved without additional pivot joints or levers. The embodiment shown in Fig. 2 and 3 is slightly modified with respect to the device shown in Fig. 1. The guide bar 24′ is placed outside the frame 10′ which consists of a square profile having two holes 21′ in the sidewalls through which the dowel 20′ extends from the beam 11′ to the pivot joint 23′. This joint is fixed to the guide bar 24′ which are guided by lugs 28′ welded to the frame. It also appears from the figs. that the dowel 20′ can be moved axially in the pivot joint in order to take up the variations in distances between the pivot joint and the beam when the guide bar is moved along the frame. Also the fastening system of the cylinder 25′ to the frame 10′ has been somewhat modified by placing the pivot shaft 29′ vertically between two brackets 30′. This means that the link joint 27′ follows the axial movement of the dowel 20′ by a swinging motion about the shaft 30′. Because of the free motion margin between the end part of the cylinder 25′ the bracket 30′ and the shaft 29′ the cylinder can however tilt in the vertical direction.

Claims: 1. Plough, preferably a reversible plough, having a frame with at least one beam to support one or preferably several plough bodies, characterized in that the plough beam (11) is supported in the frame (10) by a three point connection in such a way that the plough beam when being released pivots about a first connecting point (at 14) at the same time as the cooperating parts of a second connecting point (at 15) are released from each other or viceversa and that the third connecting point is a pivot joint (23) which is movably fastened to the frame (10) for adjusting the width of the ridge. 2. Plough according to claim 1, characterized in that the third connec­ ting point (23) is fastened to an element (24) which is movable in the length direction of the plough frame. 3. Plough according to any of the preceeding claims, characater­ ized in that the three connecting points in the working position of the plough are placed at the tips of a vertically placed triangle the third connecting point (23) in a side view being placed between the first and second connection point. 4. Plough according to any of the preceeding claims, characterized in that the plough beam (11) is provided with means (20) extending from the third connecting point (23) to an area of the plough beam which seen in a side view is situated between the first and second connection point said means being acted on by a force creating element (25). 5. Plough according to claim 4, characterized in that the force crea­ ting element (25) is pivotally fastened to the frame (10) and in said means (20). 6. Plough according to claim 4 or 5, characterized in that the force creating element (25) is a pressure mechanical component. 7. Plough according to any of claims 4 to 6, characterized in that the connection of the means (20) to the plough beam (11) seen in the direction of movement is placed behind an imagine line connecting the first and second connecting point. 8. Plough according to any of the preceeding claims, characterized in that it is equiped with means (16) for adjusting the first and/or second connecting point with respect to the frame (10). 9. Plough according to any of claims 4-8, characterized in that the point of action of the force creating element (25) on the means (20) is placed closer to the line connecting the first and second connecting points than the third connecting point.

Inventors: ANDERSSON, LARS YNGVE
Applicants: AKTIEBOLAGET OVERUMS BRUK
Application year: 1987
Main classification: A01B61
IPC codes: A01B15, A01B61