Plough

Abstract

The invention relates to a plough comprising a saddle (1) formed as a plate having an upper portion (2) and a flat lower portion (3), a ploughshare (5) formed as a plate extending parallelly to the flat lower portion (3) of the saddle (1), one or more elastic elements (8) extending perpendicularly to the plane of the ploughshare (5) between the flat lower portion (3) of the saddle (1) and the ploughshare (5), said one or more elastic elements (8) being stress free in the resting state of the plough. One or more pairs of holes (12,13) having a common axis are formed perpendicularly to the plane of the ploughshare (5), said one or more pairs of holes (12, 13) consisting of a hole (12) formed in the flat lower portion (3) of the saddle (1) and a hole (13) formed in the ploughshare. The ploughshare (5) is connected to the saddle (1) by a joint (15) having a rotation axis parallel to the plane of the ploughshare (5), and a pin (14) is positioned in each pair of holes, one end of which being firmly attached to the ploughshare (5).

Description

[0001] Plough

[0002] The present invention relates to a plough, and more particularly to a plough adapted to be mounted on an agricultural machine.

[0003] Soil tillage is an agricultural operation having a particularly high energy requirement. The draught force acting on the plough is one factor affecting the energy requirement and depends among others on the configuration of the plough and the soil parameters, typically the structure, the cohesion, the moisture, the composition and the temperature of the soil. Selfvibrating ploughs configured to vibrate during operation without using any external actuator are used to reduce the draught force.

[0004] “Vibrated tilling tools for energy saving” (Fenyvesi L. and Huboda Z., Tarim Makinalari Bilimi Dergisi, Journal of Agricultural Machinery Science, 2009) discloses a plough shown in Fig. 1 provided with an elastically supported ploughshare 104 adapted to vibrate during operation of the plough.

[0005] As shown in Fig. 1, the plough according to the prior art comprises a saddle 101 formed as a plate having a flat lower portion and being firmly connected to the mouldboard 102 of the agricultural machine via a spacing plate 103. The prior art plough further comprises a ploughshare 104 formed as a plate extending parallelly to the plane of the saddle 101. One or more springs 105 extending perpendicularly to the plane of the ploughshare are arranged between the ploughshare 104 and the lower portion of the saddle 101, said springs 105 being stress free in the resting state of the plough. One or more holes 106 having a common axis are formed in the lower portion of the saddle 101 and in the ploughshare 104 perpendicularly to the plane of the ploughshare 104. A screw 107 is positioned in the hole 106 and passes through the spring 105. One end of the screw 107 is firmly attached to the ploughshare 104, while the other end is clamped against the saddle 101 by a nut 108. A flat supporting surface 109 provided on the ploughshare 104 is in contact with and is able to roll on a rolling surface 110 of the mouldboard 102 formed as a cylindrical shell having an axis parallel to the direction of extension of the ploughshare 104. The flat support surface 109 and the rolling surface 110 formed as a cylindrical shell constitute the axis of rotation of the prior art plough configured as an oscillation system. During ploughing operation, the force acting on the plough changes, and thus the draught force requirement of the plough changes. Indeed, when a soil portion in front of the plough breaks off, the force acting on the plough decreases, and then when another soil portion is compacted, the force acting on the plough continuously increases until a further soil portion breaks off. This process repeats periodically during ploughing. Therefore, the draught force changes periodically.

[0006] In the operating state of the plough according to the state of the art, the draught force parallel to the direction of extension of the ploughshare 104 causes the supporting surface 109 of the ploughshare 104 to roll down on the rolling surface 110 of the mouldboard 102, thereby the ploughshare 104 rotates relative to the mouldboard 102 and is able to vibrate owing to the spring support 105.

[0007] The disadvantage of the prior art solution of Fig. 1 is that the support forming the aforedescribed pivot point is unstable during operation. Furthermore, the cultivated soil portion may be trapped in said support. Moreover, the connection of the ploughshare 104 and the saddle 101 via the screw 107 provided with the nut 108 limits the deformation of the spring 105 enabling only a smaller rotation angle and therefore only small amplitude vibrations. Therefore, the plough according to the prior art enables only a limited reduction of the draught force due to its relatively rigid configuration.

[0008] It is an object of the invention to overcome the above-mentioned drawbacks and to provide a plough requiring significantly reduced draught force.

[0009] These objects are achieved by providing a plough as defined in claim 1. Various preferred embodiments of the invention are specified by the dependent claims.

[0010] The present invention will now be described in detail with reference to the accompanying drawings, in which:

[0011] Fig. l is a lateral cross-sectional view of a plough according to the prior art.

[0012] Fig. 2 is a lateral cross-sectional view of the plough according to the invention in a resting state. Fig. 3 is a perspective view of the plough according to the invention in a resting state.

[0013] Fig. 4 shows the draught force acting on the plough according to the invention and the draught force acting on the prior art plough of Fig. 1 as a function of the ploughing speed. As shown in Figs. 2 and 3, the plough according to the invention comprises a saddle 1 formed as a plate having an upper portion 2 and a flat lower portion 3. The saddle 1 may be fastened at its upper portion 2 to a plough shank on the frame of the agricultural machine. The saddle 1 may be formed as a curved plate.

[0014] The plough further comprises a ploughshare 5 formed as a plate extending parallelly to the flat lower portion 3 of the saddle 1. The ploughshare 5 shown in Fig. 3 is of an elongated shape. For example, the ploughshare 5 may be provided at one end of its soil facing edge 6 with a protruding part 7 extending towards the soil. Ploughshares of other shapes are also contemplated.

[0015] One or more elastic elements 8 extending perpendicularly to the plane of the ploughshare 5 are positioned between the lower portion 3 of the plane of the saddle 1 and the ploughshare 5. The one or more elastic elements 8 are stress free in the resting state of the plough shown in Figs. 2 and 3. The elastic element 8 may be supported on both sides in its extension direction by a respective recessed support surface 9, 10 formed respectively on the lower portion 3 of the saddle 1 and on the side of the ploughshare 5 facing the saddle 1. In the resting state, the ploughshare 5 and the saddle 1 may be spaced from each other by the elastic element 8. In the preferred embodiment depicted in Fig. 3, three elastic elements 8 are positioned next to each other in a direction parallel to the extension plane of the ploughshare 5.

[0016] One or more pairs of holes 12,13 are formed perpendicularly to the plane of the ploughshare 5 and consist, as shown in Fig. 2, of a hole 12 passing through the saddle 1 and a hole 13 passing through the ploughshare 5. In the embodiment shown in Fig. 3, three pairs of holes are formed next to each other in a direction parallel to the extension plane of the ploughshare 5.

[0017] A respective pin 14 is positioned in each pair of holes and has one end firmly attached to the ploughshare 5. As shown in Fig. 2, the end of the pin 14 facing the saddle 1 may be left free and the diameter of the hole 12 formed in the flat lower portion 3 of the saddle 1 may be slightly larger, than the diameter of the pin 14. The pin 14 may extend at least along the entire length of the hole 12, whereas it may extend to the outer side of the ploughshare 5 in the hole 13 formed in the ploughshare 5.

[0018] The ploughshare 5 is connected to the saddle 1 by a joint 15 having a rotation axis parallel to the plane of the ploughshare 5, thanks to which the plough according to the invention configured as an oscillating system has a more stable rotation axis than the prior art plough of Fig. 1. Fig. 3 illustrates a preferred embodiment of the joint 15. The joint 15 may have a separate hinge pin 16, which is positioned in hinges firmly attached, preferably welded on the saddle 1 and the ploughshare 5. The hinges 17 on the saddle side and the hinges 18 on the ploughshare side may follow each other alternately. The ends of the hinge pin 16 are blocked in the longitudinal direction at the hinges provided at the extremities, in this present case at the hinges

[0019] 18 provided on the ploughshare side. Thus, the joint 15 so formed enables only a rotation around its axis.

[0020] As shown in Figs. 2 and 3, the elastic element 8 is preferably provided as a ring-shaped elastic element, which is arranged concentrically with the pair of holes, and through the inside of which the pin 14 is inserted. In this embodiment, the elastic element 8 preferably consists of disc springs 19 connected in series or in parallel or may be provided as a spiral spring. The connection of the disc springs 19 may be in series and / or in parallel. The number of disc springs

[0021] 19 may be adjusted as required. Thus, the value of the stiffness of the elastic element 8 can be easily adjusted in a discrete manner according to the given application. The required stiffness depends, for example, on the soil conditions, i.e. typically on the structure, the composition, the cohesion, the moisture and the temperature of the soil.

[0022] In the case where an elastic element 8 of a short length is installed, if necessary, for example one or more spacer washers may be positioned adjacently to the elastic element 8 on the respective supporting surface 9, 10, in order to ensure an adequate distance between the ploughshare 5 and the saddle 1.

[0023] The operation of the plough according to the invention will be described below. The plough may be mounted on a frame towed by an agricultural machine or may be suspended or semi-suspended. In the operating state, the edge 6 of the ploughshare 5 facing the soil is essentially parallel to the ploughing direction. Then, under the counterforce exerted by the soil and the draught force, the ploughshare 5 inserted into the soil performs an oscillating movement around the axis of the joint 15. Under the effect of the draught force having an amplitude periodically varying along the ploughing path, the ploughshare 5 supported relative to the saddle 1 by the one or more elastic elements 8 vibrates in a direction perpendicular to its extension plane. During vibration of the ploughshare 5, at a given outwardly oriented rotation angle of the ploughshare 5, the pin 14 abuts against the edge of the hole 12 formed in the saddle 1, thus preventing the ploughshare 5 from rotating out with respect to the saddle 1. The advantage of the plough according to the invention compared to the more rigid prior art plough of Fig. 1 is that the end of the pin 14 guiding the ploughshare 5 relative to the saddle 1 is left free, which allows for a greater deformation of the springs, thus a greater amplitude of vibration, and finally a greater reduction of the draught force.

[0024] In the preferred embodiment shown in Figs. 2 and 3, the pin 14 is arranged coaxially relative to the annularly shaped elastic element 8, so that the pin 14 also serves to position the elastic element 8 in the resting state and the operating state of the plough.

[0025] Fig. 4 illustrates the average of the draught forces measured on ploughs according to the invention equipped with elastic elements of different stiffnesses as a function of the nominal ploughing speed. The dashed line corresponding to the triangular measurement points plots the draught force acting on the prior art plough of a rigid configuration shown in Fig. 1, whereas the solid line corresponding to the dotted measurement points plots the draught force acting on the plough according to the invention as shown in Fig. 2. The draught force acting on the plough was investigated at three different nominal ploughing speeds of 3.5 km / h, 5.0 km / h and 7.0 km / h, respectively. The measurements were carried out at a temperature of 12 °C on ploughs inserted at a working depth of 28 cm in a soil having an Arany type cohesion coefficient of 45 and a moisture content of 27.9% by volume. It can be clearly seen that, compared to the prior art plough of Fig. 1, a reduction of the draught force between 3.5% and 9% can be achieved with the plough according to the invention.

[0026] The vibration of the ploughshare 5 perpendicular to the ploughing direction results in a reduction of the viscosity of the soil, a reduction of the friction coefficient between the soil and the plough, and a short-cycle fatigue of the soil. As a result, the draught force acting on the plough is lower compared to the draught force acting on the prior art plough having a rigid coupling.

[0027] The draught force acting on the plough depends on the vibration frequency and the amplitude of the ploughshare 5, which are a function of the structural configuration of the plough, the soil cultivation parameters and the condition and type of the soil. Owing to the plough according to the invention, the reduction of the draught force can be achieved by optimising the vibration parameters.

[0028] Reduction of the draught force may be achieved for example by adjusting the stiffness of the elastic element 8 according to the soil parameters. In the preferred embodiment shown in Figs. 2 and 3, it is possible to adjust the stiffness of the elastic element 8 in a discrete manner, for example, via the number of disc springs 19 constituting the elastic element 8 and via the connection therebetween in series or in parallel.

[0029] During the vibration of the ploughshare 5, the only friction surface hindering movement are the lateral edge and the soil facing edge 6 of the ploughshare 5. The resonance of the ploughshare 5 and one of the components of the draught force results in a reduction of the draught force. A further advantage of the plough according to the invention is that reduction of the draught force acting on the plough can be simply achieved by vibrating only a portion of the plough, while maintaining a low degree of friction between the ploughshare 5 and the soil.

[0030] In summary, the configuration of the plough according to the invention enables to reduce the draught force over a wide range of ploughing speeds and in various soils. Thus, fuel consumption of the agricultural machine can be reduced, which allows for cost-effective and more sustainable soil cultivation.

Claims

Claims1. A pl ough compri si ng :- a saddle (1) formed as a plate having an upper portion (2) and a flat lower portion (3),- a ploughshare (5) formed as a plate extending parallelly to the flat lower portion (3) of the saddle (1),- one or more elastic elements (8) extending perpendicularly to the plane of the ploughshare (5) between the flat lower portion (3) of the saddle (1) and the ploughshare (5), said one or more elastic elements (8) being stress free in the resting state of the plough, wherein one or more pairs of holes (12,13) having a common axis are formed perpendicularly to the plane of the ploughshare (5), said one or more pairs of holes (12,13) consisting of a hole (12) formed in the flat lower portion (3) of the saddle (1) and a hole (13) formed in the ploughshare, characterised in that the ploughshare (5) is connected to the saddle (1) by a joint (15) having a rotation axis parallel to the plane of the ploughshare (5), and a pin (14) is positioned in each pair of holes, one end of which being firmly attached to the ploughshare (5).

2. The plough according to claim 1, characterised in that the elastic element (8) is of an annular shape and is positioned concentrically with the pair of holes, and the pin (14) is inserted through it.

3. The plough according to claim 2, characterised in that the elastic element (8) consists of disc springs (19) connected in series and / or in parallel.

4. The plough according to claim 2, characterised in that the elastic element (8) is a spiral spring.

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