GB2259839A

GB2259839A - Plough body position control device

Info

Publication number: GB2259839A
Application number: GB9220165A
Authority: GB
Inventors: Oddbjorn Eliassen
Original assignee: Kverneland Klepp AS
Current assignee: Kverneland Klepp AS
Priority date: 1991-09-24
Filing date: 1992-09-24
Publication date: 1993-03-31
Anticipated expiration: 2012-09-24
Also published as: SE9202743D0; NO913739D0; FR2681499A1; SE508048C2; DE4232067C2; GB9220165D0; SE9202743L; NO173311C; NO913739L; GB2259839B; FR2681499B1; DE4232067A1; NO173311B

Abstract

There is disclosed a plough body position control device which comprises a plough frame (not shown), a plough beam (1) pivotally mounted on the plough frame and carrying a plough body (1') and in which the plough beam is capable of pivoting relative to the plough frame in response to variation in ploughing load applied to the plough body during ploughing e.g. when encountering a buried stone or other obstacle, hold-down means (3, 4) for exerting a hold-down force on the plough body (1') during ploughing and which includes a hydraulic piston/cylinder arrangement (5) to control the hold-down force exerted on the plough body: in which the overload control device comprises a pressure source (8) connected to the piston/cylinder arrangement (5) via a pressure controller (9), a sensor (10) arranged to monitor the position taken-up by the plough beam (1) relative to the plough frame and to respond to movement of the plough beam (1) with the sensor being arranged to issue corresponding sensor signals, and a processor unit (12) arranged to receive signals from the sensor (10) so as to vary the hold-down force exerted on the plough body (1') in response to variation in ploughing load applied to the plough body. <IMAGE>

Description

PLOUGH BODY POSITION CONTROL DEVICE This invention relates to a plough

body position control device which comprises a plough frame, a plough beam pivotally mounted on the plough frame and carrying a plough body and in which the plough beam is capable of pivoting relative to the plough frame in response to variation in ploughing load applied to the plough body during ploughing e.g. upon encountering a buried stone or other obstacle, hold-down means for exerting a hold-down force on the plough body during ploughing and which includes a hydraulic piston cylinder arrangement, and an automatically acting overload control device coupled with the piston / cylinder arrangement to control the hold-down force exerted on the plough body.

In the provision of an automatically acting stone and overload security or safety device for the or each plough body (or pair of plough bodies in a reversible plough), the following general requirements should be complied with: (i) the force with which the plough body is retained in working position in the soil during ploughing shall not be larger than necessary; (ii) said force shall be somewhat larger than the largest resistance against ploughing (ploughing resistance) one can count on at any time, so that the plough body respectively each plough body is maintained steadily in place in ploughing position in the soil; (iii) when a plough body hits a stone or an overload situation occurs in some other way, the plough body shall slide as easy as possible over the stone and thereafter approximately follow the contours of the same, whereafter the plough body is to return to working position as soon as it has passed the stone respectively or as soon as the overload situation is neutralised; (iv) when one plough body of several plough bodies hits a stone, the above-mentioned security or safety process should not influence the other plough bodies, nor the remaining plough structure; this remains contingent on the fact that the plough body influenced by a stone is not retained with too large a force.

Generally, the invention seeks to provide an overload control device in a plough body position control device of the kind concerned which satisfies the above-mentioned general requirements, so that the device secures that the plough body is maintained in a steady working position in the soil during ploughing, i.e. with a force which only slightly exceeds the maximum ploughing resistance force which may be counted on during the existing ploughing conditions, which especially is determined by the kind of soil present. When a plough body hits a stone within the soil or otherwise if the load acting on the plough body becomes too large, the device according to the invention shall secure that the plough body may yield and, if necessary, swing up from the soil. The force with which the plough body is retained, is to be controlled in the various positions of the plough body. When the stone or other obstacle has been passed, the plough body is to be automatically urged back again into normal ploughing position.

A preferred objective of the invention ensures that the force needed to bring the plough body to yield, may be controlled in relation to how firm the soil is.

Among previously known solutions wherein one or more of the abovementioned partial objects are realised, Norwegian patent specification No 134354 may be mentioned.

This patent specification discloses a plough beam equipped with a spring mechanism allowing the plough body automatically to swing upwards whenever it hits an obstacle within the soil. This known plough beam distinguishes itself particularly through having a joint allowing movements of the plough body also in the lateral directions and other directions of movement intermediate the horizontal and vertical planes. Said joint may comprise two parts maintained resting against each other by means of the spring mechanism, said joint parts being able to tilt in relation to each other, and wherein the spring(s) is / are so tensioned that the joint parts are resting completely against each other when the plough body works in normal soil.

p T, 4 In the device according to Norwegian patent specification No 134354, according to one embodiment, one has used a leaf spring offering the necessary counter force.

In another known solution, this leaf spring is replaced' by a hydraulic cylinder. Moreover, further known solutions exist; these being based on various principles for power transmitters and power transfer mechanisms.

A common disadvantage in all known solutions is that it is laborious and time-consuming to change the counter force acting on the plough body. The term "plough body" in this connection is also meant to cover a pair of plough bodies of the type used in reversible ploughs, and which is mounted on a common plough beam, wherein one plough body of the pair occupies an active plough position, while the other plough body occupies an inactive position of readiness; for such plough body pairs it is sufficient that an automatic stone and overload security device is assigned to the common plough beam, e.g. one device for each individual plough body or for each pair of reversible plough bodies.

In known devices of the kind concerned, it is even more difficult to change the power characteristic, i.e. the variation of the force with which the plough body is retained when it hits a rock and is urged upwards.

None of the hitherto known solutions allows automatic adaption of said counter force during varying soil conditions during ploughing.

The present invention seeks to overcome deficiencies, disadvantages and limitations of use associated with known stone and overload security devices for ploughs, and to provide a novel device capable of adjusting itself automatically to the existing soil conditions, so that the user does not have to think of settings or adjustments.

According to the invention there is provided a plough body position control device which comprises:

plough frame; plough beam pivotally mounted on the plough frame and carrying a plough body, said plough beam being capable of pivoting relative to the plough frame in response to variation in ploughing load applied to the plough body during ploughing; means for exerting a hold-down force on the plough body during ploughing and which includes a hydraulic piston cylinder arrangement; and an automatically acting overload control device coupled with the piston / cylinder arrangement to control the holddown force exerted on the plough body:

characterised in that the overload control device comprises a pressure source connected to the piston cylinder arrangement via a pressure controller; a sensor arranged to monitor the position taken-up by the plough beam relative to the plough frame and to respond to movement of the plough beam, said sensor being arranged to issue corresponding sensor signals; and, a processor unit arranged to receive the sensor signals from the sensor and connected to the pressure controller so as to vary the hold-down force exerted on the plough body in response to variation in ploughing load applied to the plough body.

Preferred aspects of the invention are set out in the dependent claims.

In an embodiment of device according to the invention, the following essential advantages are achieved: (i) timeconsuming adaption and adjustment are eliminated; (ii) the plough will run more steadily than before; (iii) the ploughing result is improved; (iv) the ploughing speed may be increased; (v) the useful life of the plough components is prolonged. All of this results in a better operational economy.

Examples of preferred embodiments of thb invention are diagrammatically illustrated in the accompanying drawings, in which:

Figure 1 shows a first embodiment of a stone and overload security device, wherein a plough body is shown in two different positions, namely in a working or ploughing I- position in solid lines and in a partly swung-up stone passing position in dotted lines; assigned electrical electronic equipment substantially being shown in block diagram form; Figure 2A shows a second embodiment of the stone and overload security device in a side elevational view, corresponding to the view of Figure 1; Figure 2B shows a third embodiment of the stone and overload security device, representing a somewhat modified design of the device according to Figure 2A, and shown in a corresponding side elevational view; and, Figure 3 shows a fourth embodiment of the stone and overload security device, shown in a side elevational view corresponding to the preceding figures.

In the four figures of the drawings, identical reference numerals have been used to denote like parts; for constructively and / or functionally similar components, similar reference designations (e.g. 10, 10a, 10b, 10c) have been used.

First, referring to Figure 1:

In this figure of the drawings, reference numeral 1 denotes a tubular plough beam which at its rear end (with respect to the ploughing direction) carries a plough body 11, which may be constituted by one plough body of a pair of plough bodies for a reversible plough (the other, inactive plough body not being shown).

At its front end, the plough beam 1 is assigned a joint 2 allowing rotation of the plough beam 1 and consequently of the plough body 11 at least in a vertical plane.

In principle, this joint 2 may be of the same kind as disclosed in Norwegian patent specification No 134354 and, thus, allow universal rotation of plough beam / plough body 1, 11 also in the lateral directions and other directions of movement intermediate the vertical and horizontal planes. Thereby, the joint 2 may comprise e.g. four balls 31 arranged on a bracket 3 which together with the balls 31 constitute one joint part, the balls 31 being adapted to engage into complementary ball seats formed in a front flange portion ill of the tubular plough beam 1, wherein said flange portion 1 incorporating ball seats constitute the other joint part.

However, this joint 2 may be formed in entirely different ways, provided that it allows rotation of the plough beam / plough body at least in a substantially vertical plane (when the plough is travelling through level ground).

The bracket 3 constituting one part of the joint 2, is rigidly attached to a plough frame, not shown, so that the bracket 3 maintains a substantially vertical position thereof, irrespective of the position of the plough beam plough body 1, 11. The solid line position for the parts 1, if and 3 is a normal ploughing position as compared with dotted line position of the same parts for a movement away from a buried obstacle.

To the bracket 3 is coupled a tension rod 4 which, when plough beam 1 and plough body 11 occupy normal ploughing position, extends centrally through the tubular plough beam 1 A similar tension rod having a corresponding connection point at the bracket 3 is known from the above-mentioned Norwegian patent specification.

At the rear end of the plough beam 1, a hydraulic cylinder 5 is concentrically coupled, the piston thereof being denoted 51 and the piston rod 5". The front end of the piston rod 5" is coupled to the rear end of the tension rod 4 through a joint 6.

To one chamber 7 of the cylinder (i.e. the chamber at the piston rod side of the piston 51 - the other chamber being denoted 71), hydraulic oil is supplied from a pressurised oil source 8. The oil pressure is controlled by means of a pressure control valve 9.

According to the embodiment shown in Figure 1, the piston 51 of the cylinder 5 is assigned a position sensor 10 adapted to record the position of piston 51 or possibly the position of the piston rod 5" within the cylinder 5.

The position sensor 10 is adapted to produce control 7- signals representative of the position of the piston 51 at any time, through a digital filter 11 to a microprocessor 12 adapted to produce control signals to the pressure control valve 9, either directly or through an appropriate controller 13.

The automatic stone and overload security device according to the embodiment shown in Figure 1 operates in the following way:

At any time a hydraulic pressure is maintained in the cylinder chamber 7 at the piston rod side of the piston 51. This causes the plough beam 1 with plough body 11 to be retained in place in normal ploughing position.

During ploughing, the position sensor 10 records varying resistance in the soil 14 through varying piston positions within the cylinder 5.

If this variation becomes too large, i.e. exceeds a predetermined value, the hydraulic pressure within the cylinder chamber 7 increases until the variation again corresponds to said predetermined value. On the other hand, if said variation should become too small, i.e. smaller than a presupposed minimum variation, the pressure within the cylinder chamber 7 is decreased until the variation again corresponds to the desired value.

If the positional deflection of the position sensor 10 becomes larger than a value determined beforehand, this is usually equivalent to the fact that the plough body 11 has hit a stone 15 or another obstacle buried within the soil 14. Then, the pressure within the cylinder chamber 7 at the piston rod side of the piston 51 is controlled dependent on the piston position, so that the desired hold-down force is achieved.

When the speed of the motion of piston 5 becomes equal to zero, this means that the plough body 11 has passed over the top of the stone 15 or another obstacle, and the pressure within the cylinder chamber 7 will then be increased to that value it had before the plough body 11 hit the stone 15 or another obstacle, so that the plough body 11 as soon as possible is brought back to normal ploughing position.

The microprocessor 12 is adapted to record and process the signals transferred thereto through the digital filter 11 from the position sensor 10, and produces on this basis thereof control signals to the pressure control valve 9. The entire process is controlled by a program made for this task, and which is implemented into the microprocessor 12.

Figure 2A shows a second embodiment of the stone and overload security device according to the invention.

This embodiment differs from the embodiment according to Figure 1 substantially therein that the cylinder chamber 7a opposite the piston rod side of the piston 51 is closed and filled with air, and that a pressure sensor 10a has been used instead of a position sensor 10 according to Figure 1.

A third embodiment according to Figure 2B represents a modification of the Figure 2A embodiment in that the air filled cylinder chamber 7a, of Figure 2A here is filled with oil. This oil filled cylinder chamber is denoted 7b, and is assigned an accumulator 16.

In the second and third embodiments, the pressure is recorded within the air chamber 7a, and the oil chamber 7b, by means of pressure sensor 10a and 10b respectively. Such air / oil pressure measurements in the cylinder chamber 7a, 7b, will have a direct relation to the plough position. Therefore, the adjustment may proceed basically as described in association to Figure 1.

Figure 3 shows a fourth embodiment of the stone and overload security device according to the invention.

As in the embodiments of Figure 2A and 2B, a pressure sensor 10c has been used in Figure 3 instead of a position sensor 10 according to Figure 1 but, according to Figure 3, the pressure sensor 10c is assigned the cylinder chamber 7c at the piston rod side of the piston, so that the pressure here is measured in the same chamber 7c wherein the pressure is controlled / adjusted.

In this embodiment, Figure 3, the control process may take place such that the pressure control valve 9 normally is -g- being kept closed. When the plough body 1 meets varying resistance in the soil, the plough body will move slightly in relation to the plough frame, and the movements are transferred to the piston 51, so that varying pressure conditions within the cylinder chambers 7c, 7c, are created. This pressure variation will be directly dependent on the movement of the plough body 11 in relation the plough frame.

The regulation may basically take place in nearly the same way as previously described. When the pressure variation becomes too large, some oil is let into the cylinder chamber 7c at the piston rod side of the piston 51, so that the pressure increases here. When the pressure variation becomes too small, i.e. drops below a predetermined minimum value, some oil is let out of the chamber 7c, so that the pressure decreases.

When the plough body 11 impinges a stone, i.e. when the pressure within the chamber 7c in the course of a short time exceeds a predetermined limit value which is e.g. 20% larger than the immediately preceding, the pressure control valve 9 opens. When the plough body 11 slides over the stone, oil is urged out through the pressure control valve 9. The opening of the valve will at all times adjust itself such that the course of pressure becomes as desired. When the plough body has moved to the top of the stone, there will be no more oil to be pressed out, and the pressure decreases to atmospheric pressure. When the pressure drops below a certain limit value, oil is guided into the system again, so that the pressure increases according to a desired pattern until the pressure again becomes the same as it was before the plough body 11 struck against the stone.

Claims

A plough body position control device which comprises:

plough frame; plough beam pivotally mounted on the plough frame and carrying a plough body, said plough beam being capable of pivoting relative to the plough frame in response to variation in ploughing load applied to the plough body during ploughing; means for exerting a hold-down force on the plough body during ploughing and which includes a hydraulic piston cylinder arrangement; and an automatically acting overload control device coupled with the piston / cylinder arrangement to control the holddown force-exerted on the plough body:

characterised in that the overload control device comprises a pressure source connected to the piston cylinder arrangement via a pressure controller; a sensor arranged to monitor the position taken-up by the plough beam relative to the plough frame and to respond to movement of the plough beam, said sensor being arranged to issue corresponding sensor signals; and, a processor unit arranged to receive the sensor signals from the sensor and connected to the pressure controller so as to vary the hold-down force exerted on the plough body in response to variation in ploughing load applied to the plough body.
2. A plough body position control device according to Claim 1, in which the overload control device is operative to cause the piston / cylinder arrangement to apply a reduced hold-down force when a predetermined ploughing load is exceeded e.g. upon the plough body encountering a buried stone or other obstacle and to allow the plough body to move away from the obstacle, and thereafter to apply increased hold-down force on the plough body to restore it to its previous ploughing position.

1 1
3. A plough body position control device according to Claim 1, in which said hold-down means, the pressure control valve, the sensor and the processor unit are arranged to adjust the hold-down force continuously, so that the plough body, when in the ploughing position, receives small vibration-like changes in relation to the plough frame as a result of varying ploughing force, and further is adapted to reduce the hold-down force as the positional changes or the time derived values of the position exceed a pre-set value.
4. A plough body position control device according to any one of Claims 1 to 3, in which said sensor is a position sensor.
5. A plough body position control device according to any one of Claims 1 to 3, in which the sensor is a pressure sensor arranged to monitor the pressure at one or the other side of a piston within the hydraulic cylinder of the piston cylinder arrangement.
6. A plough body position control device according to Claim 5, in which a chamber is defined within the cylinder on the side of the piston remote from the piston rod, and said chamber is closed and air-filled, and in which the pressure sensor is associated with this chamber.
7. A plough body position control device according to Claim 5, in which a chamber is defined in the cylinder on the side of the piston remote from the piston rod, and is filled with pressure liquid, and in which said pressure sensor is associated with this pressure chamber.
8. A plough body position control device according to Claim 7, in which an accumulator is coupled with said cylinder chamber.
9. A plough body position control device according to any one of Claims 1 to 8, in which a digital filter is connected between the sensor and the processor.
10. A plough body position control device according to any one of Claims 1 to 9, in which a controller is connected between the processor and the pressure control valve.
11. A plough body position control device according to any one of Claims 1 to 10, in which the pivotal connection between the plough beam and the plough frame is such as to allow pivotal movement of the plough body in at least an upright plane in response to variation in ploughing load applied to the plough body.
12. A plough body position control device according to Claim 11, in which the pivotal connection between the plough beam and the plough frame is a universal connection.
13. A plough body position control device according to any one of Claims 1 to 12, including a plurality of plough beams each pivotally mounted on the plough frame, and each carrying at least one respective plough body.
14. A plough body position control device according to Claim 13, in which at least a pair of reversible plough bodies is carried by each plough beam, and the plough frame is adjustable between two different working positions in order to bring one or the other of the plough bodies in each pair into a ploughing position.
15. A plough body position control device according to Claim 1, and substantially as hereinbefore described with reference to, and as shown in any of the embodiments illustrated in the accompanying drawings.