GB2057837A - Method and apparatus for controlling a harvesting combine - Google Patents

Abstract

An apparatus for controlling the forward speed of a harvesting combine comprises means 11 responsive to the torque in a drive 10 for a harvesting unit 15 of the combine, means 7 for sensing the grain loss at a straw separating unit 6 of the combine and means 2 responsive to the speed of a ground wheel 1 of the combine. Desired maximum values of the aforesaid torque, grain loss and ground speed may be set in a unit 16 and control signals are supplied to an actuator 17 when the desired levels are exceeded, to reduce the speed of a main drive (not shown) of the combine. The response of the main drive to the control signals may be adjusted by a device 18. <IMAGE>

Description

SPECIFICATION Method and apparatus for controlling a harvesting combine The invention relates to a method and apparatus which are usable for regulation of the load of harvesting combines which includes a straw racking and separating unit and a harvesting unit, the harvesting unit comprising, for example, a cutting device for grain or a snapper unit for corn.

When harvesting is being carried out by a modern heavy-duty harvesting combine the selection of the value of the work rate of the combine is one ofthe principle problems. The load of the combine must be determined in order to assure the optimal conditions of an economical upkeep of the combine. The optimality of the conditions may be explained in the following way. Maximum efficiency of the combine can be attained by operating the combine at a maximum ground speed consistent with assuring a predetermined low loss level of the harvested grain. The grain loss level is generally required to be lower than 1.5%.

A known regulating system is provided for Soviet combines of the SK-5 type. This system operates through measuring the load of the thresher drum in the combine. If the measured load increases to a non-permissible value, it results in an action to decrease the forward speed of the combine.

Decrease of the forward speed of the combine results in a decrease in the quantity of the crop transported from the harvester unit of the combine, and in this way the danger of clogging the thresher drum can be avoided.

Another known method exploits uses elements which are located at the straw rack or the screen of the combine. The outputs of the sensing elements give signals which have a value proportional to the grain loss level and which are transmitted to the driver's cabin of the combine. In this way the driver gathers information about the grain loss level and he can take the necessary steps for decreasing the grain losses. This method does not provide automatic regulation, and because the crop passes through the combine in a time of between 5 to 10 seconds, is insufficiently fast to prevent an unacceptable grain loss.

West-German patent specification 1,199,039 describes a device for regulating the work load of automotive harvesting machines. This device is equipped with movable sensing elements, whose displacement is measured. The measured value of the displacement is transformed into a signal having a value that characterises the quantity of the crop being guided into the machinery. The value of the displacement depends on the load of the machinery being a function of the forward speed. Therefore, the forward speed ofthe machinery can be regulated by a mechanical or a hydraulic transmission for keeping it under a preselected value which is generally dependent on the actual soil and ground conditions.

This solution ensures a satisfactory work load of the combine, but the grain loss level can overstep a permissible value. The overstepping comes from the fact that in this method of regulation many factors are not taken into account.

In West-German patent specification 1,923,779 a movable sensing element is described that is associ ated with a belt of a chain gear ofthe combine. The displacement of the sensing element is transmitted by a sun-and-planet gear to the drive mechanism.

This solution can be characterized by the same disadvantages as the above described ones.

In West-German patent specification 1,265,476 a device has been proposed for regulating the speed of the thresher drum ofthe combine. Regulation is based on the quantity of the crop being transported by an intake auger conveyor unit. The device renders possible avoidance of the danger of clogging the thresher drum by the crop within a permissible limit value.

What is desired is a method and apparatus for ensuring that an economically optimal engine load is associated with a grain loss level which does not exceed a preselected maximum value.

The present invention is based on the perception that the measure of grain loss can be determined from the torque required by the harvesting unit of the combine. If the forward speed is regulated on the basis ofthetorque required by the drive of the harvesting unit, the regulating system can be constructed in such a way that the grain loss level will be under an upper limit, the drive will work at a possible maximal value ofthe required torque and the forward speed will correspond to the soil and ground conditions.

According to the invention there is provided a method of controlling operation of a harvesting combine which includes a harvesting unit and a straw separating unit the method including the steps of setting maximum acceptable levels of the speed of the combine preferably depending on the soil and ground conditions, of measuring the moving speed, of regulating the moving speed depending on the quantity or on the thickness of the corns in a value domain running to the maximal value, wherein the improvement lies in that comprising further steps of defining a maximal value of the permissible loss level ofthe corn and a maximal value ofthe moment being measured at the drive of the straw racking and separating unit, of measuring the value of the loss level and of the moment being required by the drive during the harvesting works, of regulating the moving speed and of the loss level on the basis of the required moment in such a way that the value of the moment and of the loss level lies in a value domain running up to the corresponding maximal value.

According to another aspect of the invention there is provided an apparatus for regulating the load of combines of the above-mentioned construction, which comprises an actuating unit being connected to a control unit, and a speed sensing device, wherein according to the proposed invention a loss sensing device is coupled with the straw racking and separating unit, a moment sensing device is associated with the drive of the harvesting unit, the sensing devices are connected each to a signal transformer unit, the outputs ofthe signal transformers are coupled over corresponding difference units with a circuit for generating a compensation signal and the circuit is connected to the actuating unit.

In a particular embodiment, control of the forward speed has a priority over the control based on the grain loss level, which in turn has a priority over regulation based on the torque required by the harvesting unit. In this way it will be ensured that the combine works with a moving speed which does not exceed its selected maximum value, and that the grain loss level is lower than its selected maximum value.

Further objects, features and advantages ofthe invention will become better understood by the following detailed description, given purely by way of example, when considered in conjunction with the accompanying drawings, wherein Figure 1, is a circuit diagram of a preferred embodiment of an apparatus for carrying out the proposed method, when used with a harvesting combine, Figure 2, is an arrangement of a control unit situated in a driver's cabin of the combine, and Figure 3 shows the placement of the elements of a regulating apparatus for realization of the proposed method.

In use, maximum acceptable values will be chosen, respectively, for the forward speed of the combine dependent on the actual soil and ground condi tions, for the torque required by the drive of the harvesting unit, and forth grain loss level atthe straw racking and separating unitofthe combine. The corresponding values are measured by respective sensing devices at corresponding locations on the combine, namely by a speed sensing device in a nondriven wheel, by a grain loss sensing device in the straw racking and separating unit and by a torque sensing device at the harvesting unit. The main driving engine of the combine drives all operating units through hydraulic transmissions which are connected to the main engine by a belt or a chain.The driven wheels are provided with a hydraulic motor or with a variator or with a vee-belt unit being coupled with the main engine. The values measured by the sensing devices are compared to the corresponding preselected maximum values. If the forward speed andlor the required torque andlor the grain loss level exceeds the corresponding preselected maximum values, the forward speed of the combine will be reduced. If the value of the grain loss level has a lower value than the permissable maximum one, and the required torque has a lower value than the corresponding permissible maximum, the forward speed will be increased.

Because of ambient conditions during harvesting a change of the maximum value of the forward speed may be necessary during operation. Advantageously it is provided that automatic control may be interrupted, and manual regulation be carried out.

The presently invented device is shown schematically on Figure 1. The device is connected to the combine structure 30 through an actuating unit 17 which is operable to select a required transmission ratio of a drive 20 of the combine. Preferably a control lever 18 is situated between the actuating unit 17 and the drive 20. The control lever 18 is associated with a switching unit 19 for interruption of automatic regulation and for permitting manual regulation. The drive 20 actuates the drive 10 of a harvesting unit 15, which may be, for example, a cutting unitforwheat or by a snapper unitforcorn. From the harvesting unit 15 the harvested crop is guided through a straw racking and separating unit 6. On Figure 1, the route of the crop is shown by a broken line R.The straw racking and separating unit 6 and the drive wheels are actuated also by the drive 20 ofthe combine.

During harvesting a non-driven wheel 1 is moving and therefore the wheel 1 is suitable for measuring the forward speed of the combine. Within the structure 30 of the combine are sensing devices 2,7, 11, namely a speed sensing device 2, built into the wheel 1, a grain loss sensing device 7, built into the straw racking and separating unit 6, and a torque sensing device 11, built in the drive 10 of the harvesting unit 15. The sensing devices 2,7, 11 are respectively connected through corresponding signal transducers 3, 8, 12 and difference units 4,9, 13 to a circuit 5 for generating a compensation signal. Each of the difference units 4, 9, 13 comprises means for generating an output signal having a logical level 0 or 1, dependent on the corresponding measured and preselected values.The output ofthe circuit 5 is connected to the actuating unit 17.

The logical outputs of the difference units 4,9, 13 are connected through pulse generators 51, 52, 53, 54 to a control circuit 56, and also directly to the circuit 56 and to a further unit 55. The unit 55 serves to define the direction of the work of the drive 20, that is to acceierate or decelerate the combine. The control circuit 56 produces output signals which are amplified by an amplifier 57 to provide a control signal for the actuating unit 17. The actuating unit 17 differentiates the control signals respectively in accordance with their periods, their widths, and their amplitudes and produces an output taking into account also the output signal ofthe unit 55.

The presently invented device may be controlled by a central unit 16 being built in the driver's cabin (Figures 2 and 3). The central unit 16 comprises knobs 21,22, 24, 26 and indicators 23, 25, 27, 28 and 29. The knobs 21, 24, 26 serve to set the maximum selected values respectively of the forward speed, of the grain loss level and of the harvester unit torque.

The knob 22 permits regulation ofthe sensitivity of the grain loss level detection. The indicators 25, 27, 28 and 29 serve respectively to indicate decrease of the moving speed in response to sensed loss level, decrease of the moving speed, increase of the moving speed and that the regulating system is operating. The indicator 23 showswhetherthe grain loss level has a minimum (MIN), optimum (OPT) or maximum (MAX) value.

The sensing devices 2, 7, 11 are mounted on the combine as indicated in Figure 3. The speed sensing device 2 is coupled with the non-driven wheel, the grain loss sensing device 7 with the straw racking and separating unit 6, and the torque sensing device 11 with the drive 10 ofthe harvesting unit 15. The outputs of the sensing devices are coupled to the central unit 16. Signals displayed on the central unit 16 can be used for regulating the work load of the combine through the actuating unit 17 by the following way: 1. By means of the knob 21 the permissible maximum value of the forward speed of the combine may be set in accordance with ambient conditions, for example the condition ofthe ground as well as on the nature of the crop, to be harvested.

2. By means of the knob 22 the sensitivity of the grain loss level measure can be determined in such a way that the signal OPT of the indicator 23 is energised at an acceptable value of the grain loss level.

The acceptable grain loss level may be determined by inspection of material discharged from the combine.

3. By means of the knob 26 the torque of the drive 10 of the harvesting unit 15 should be selected to correspond to the crop to be harvested. This value must preferably be selected in such a way that quickening or slowing down ofthe combine will be unnecessary, whereby the indicators 27 and 28 are not energised.

When the forward speed being measured by the speed sensing device 2 exceeds the maximum value set by the knob 21, the circuit 5 generates a command signal that acts on the drive 20 through the actuating, - unit 17 to slow down the combine. This regulating function is independent ofthe signals of the grain loss sensing device 7 and of the torque sensing device 11 as well as from the signals of the difference units 9, 13.

If the grain loss sensing device 7 gives signals indicating that grain loss exceeds the permissible level set by the knob 24, the circuit 5 generates a command signal that acts through the unit 17 to slow down the forward speed. The reduction in speed causes a decrease of the grain loss level. This regulating function is independent of the signals of the torque moment sensing device 12 as well as those from the difference unit 13.

If the torque has a sensed value which is different from the desired value, the circuit 56 provides signals which result in corresponding quickening or in slowing down the combine.

Claims (8)

1. A method of controlling operation of a harvesting combine which includes a harvesting unit and a straw separating unit, the method including presetting maximum acceptable of grain loss and ofthe torque on a drive to said harvesting unit, and regulating the speed of the combine in accordance with differences between the sensed and the preset values ofsaidtorque and said grain loss level respectively.

2. A method as claimed in claim 1 which includes presetting a maximum acceptable level of the speed of the combine.

3. An apparatus for controlling operation of the speed of a harvesting combine which includes a harvesting unit and a straw separation unit, said apparatus comprising means for providing a first signal dependent on a sensed level of grain loss, means for providing a second signal dependent on a sensed level of torque on a drive of said harvester unit, means for setting the levels of third and fourth signals which are respectively indicative of maximum acceptable values of grain loss and harvester unit drive torque, means for providing a signal indicative of a sensed forward speed of the combine, a control circuit, responsive to differences between said first and third signals and between said second and fourth signals, for generating output signals, and an actuator unit for varying the speed of the combine in accordance with said output signals.

4. An apparatus as claimed in claim 3 which includes means for providing a signal indicative of a desired maximum value of said forward speed, said control circuit providing a further output signal to said further actuator unit in response to a difference between said sensed and said desired maximum values of forward speed.

5. An apparatus as claimed in claim 3 or claim 4 which includes a regulating means between said actuator unit and a main drive of the combine, for varying the speed of said main drive for a given value of output signal from said control circuit.

6. An apparatus as claimed in any of claims 3 to 5 which includes means for providing a display when any of said output signals is present.

7. A method of controlling a harvesting combine, substantially as hereinbefore described, with reference to the accompanying drawings.

8. An apparatus forcontrolling a harvesting combine, substantially as hereinbefore described, with reference to the accompanying drawings.