CA1146661A - Grain loss indicator having a sensor member secured to a shaken with a sieve frame - Google Patents
Grain loss indicator having a sensor member secured to a shaken with a sieve frameInfo
- Publication number
- CA1146661A CA1146661A CA000307242A CA307242A CA1146661A CA 1146661 A CA1146661 A CA 1146661A CA 000307242 A CA000307242 A CA 000307242A CA 307242 A CA307242 A CA 307242A CA 1146661 A CA1146661 A CA 1146661A
- Authority
- CA
- Canada
- Prior art keywords
- straw
- sensor
- sieves
- grain loss
- sensor member
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000013078 crystal Substances 0.000 claims abstract description 19
- 239000000463 material Substances 0.000 claims abstract description 16
- 239000010902 straw Substances 0.000 claims description 43
- 239000002184 metal Substances 0.000 claims description 24
- 241001272996 Polyphylla fullo Species 0.000 claims description 20
- 230000033001 locomotion Effects 0.000 claims description 11
- 241000251169 Alopias vulpinus Species 0.000 claims description 9
- 238000003306 harvesting Methods 0.000 claims description 3
- 230000035945 sensitivity Effects 0.000 claims description 3
- 239000000919 ceramic Substances 0.000 abstract description 2
- 235000013339 cereals Nutrition 0.000 description 22
- 239000003990 capacitor Substances 0.000 description 7
- 239000003351 stiffener Substances 0.000 description 4
- 241001124569 Lycaenidae Species 0.000 description 3
- 240000004658 Medicago sativa Species 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000010903 husk Substances 0.000 description 2
- 244000075850 Avena orientalis Species 0.000 description 1
- 235000007319 Avena orientalis Nutrition 0.000 description 1
- 240000005979 Hordeum vulgare Species 0.000 description 1
- 235000007340 Hordeum vulgare Nutrition 0.000 description 1
- 235000010624 Medicago sativa Nutrition 0.000 description 1
- 235000017587 Medicago sativa ssp. sativa Nutrition 0.000 description 1
- 240000007594 Oryza sativa Species 0.000 description 1
- 235000007164 Oryza sativa Nutrition 0.000 description 1
- 241000209140 Triticum Species 0.000 description 1
- 235000021307 Triticum Nutrition 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 230000003116 impacting effect Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 235000009566 rice Nutrition 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01D—HARVESTING; MOWING
- A01D41/00—Combines, i.e. harvesters or mowers combined with threshing devices
- A01D41/12—Details of combines
- A01D41/127—Control or measuring arrangements specially adapted for combines
- A01D41/1271—Control or measuring arrangements specially adapted for combines for measuring crop flow
- A01D41/1272—Control or measuring arrangements specially adapted for combines for measuring crop flow for measuring grain flow
- A01D41/1273—Control or measuring arrangements specially adapted for combines for measuring crop flow for measuring grain flow for measuring grain loss
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/045—Analysing solids by imparting shocks to the workpiece and detecting the vibrations or the acoustic waves caused by the shocks
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/36—Detecting the response signal, e.g. electronic circuits specially adapted therefor
- G01N29/42—Detecting the response signal, e.g. electronic circuits specially adapted therefor by frequency filtering or by tuning to resonant frequency
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/44—Processing the detected response signal, e.g. electronic circuits specially adapted therefor
- G01N29/46—Processing the detected response signal, e.g. electronic circuits specially adapted therefor by spectral analysis, e.g. Fourier analysis or wavelet analysis
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/10—Number of transducers
- G01N2291/101—Number of transducers one transducer
Abstract
ABSTRACT OF THE DISCLOSURE
Sensor member having on it a ceramic crystal, is secured to a sieve or sieve frame of a combine harvester to be shaken with the sieve or sieve frame being so located that any grain which is discharged from the sieve and otherwise wasted will impact upon the sensor and cause an electrical signal to be transmitted by the crystal, the signal being amplified and transmitted to a readout station which enables the operator to immediately identify when grain is wasted. In being shaken along with the sieve the sensor presents a clean face to the grain, which might otherwise be partly obscured by chaff or other discrete material and this results in a higher degree of accuracy in the determination of wasted grain.
Sensor member having on it a ceramic crystal, is secured to a sieve or sieve frame of a combine harvester to be shaken with the sieve or sieve frame being so located that any grain which is discharged from the sieve and otherwise wasted will impact upon the sensor and cause an electrical signal to be transmitted by the crystal, the signal being amplified and transmitted to a readout station which enables the operator to immediately identify when grain is wasted. In being shaken along with the sieve the sensor presents a clean face to the grain, which might otherwise be partly obscured by chaff or other discrete material and this results in a higher degree of accuracy in the determination of wasted grain.
Description
This invention relates to an indicator which is useful ~or indicating the grain loss from a combine harvester.
BACKG~OUND OF' THE INVENTION
~ . _ .
Because of wide variations which occur in crops which 5. are harvested, a need has been recognised for an indicator which will indicate the grain 105s.
When a crop is harvested, the stalk and heads are cut off at about mid length, and fed into a thresher. The husks are blown out by a fan situated beneath the thresher.
10. If there is too much draft the fan will cause excessive quantities of grain to be blown out with the husks. Straw is also thrown onto the straw walkers of the combine, and the straw walker carry the straw to the back of the machine and on the ground. If there is too much intake by the 15. machine for the capacity of the thresher, the thresher becomes overloaded and does not fully thresh all the heads of the stalks, and this also leads to grain loss along with the straw as it is discharged from the walkers.
This problem has been recognised, and in the United 20. States Patent 3,593,720 to J.R. Botterill and U.S. Patent No. 3,606,745 to J. C. F. Girodat, grain loss monitors were disclosed which were arranged to detect the number of grain kernels passing per unit of time at the discharge end of the walker or the sieves. There have been developments on 25. these early Patents, and in the U.S. Patent, 3,939,~46 to Drozhzhin et al. there was described a device which included a transducer for measuring the amount of grain lost by the thresher and a transducer for measuring the amount of grain
BACKG~OUND OF' THE INVENTION
~ . _ .
Because of wide variations which occur in crops which 5. are harvested, a need has been recognised for an indicator which will indicate the grain 105s.
When a crop is harvested, the stalk and heads are cut off at about mid length, and fed into a thresher. The husks are blown out by a fan situated beneath the thresher.
10. If there is too much draft the fan will cause excessive quantities of grain to be blown out with the husks. Straw is also thrown onto the straw walkers of the combine, and the straw walker carry the straw to the back of the machine and on the ground. If there is too much intake by the 15. machine for the capacity of the thresher, the thresher becomes overloaded and does not fully thresh all the heads of the stalks, and this also leads to grain loss along with the straw as it is discharged from the walkers.
This problem has been recognised, and in the United 20. States Patent 3,593,720 to J.R. Botterill and U.S. Patent No. 3,606,745 to J. C. F. Girodat, grain loss monitors were disclosed which were arranged to detect the number of grain kernels passing per unit of time at the discharge end of the walker or the sieves. There have been developments on 25. these early Patents, and in the U.S. Patent, 3,939,~46 to Drozhzhin et al. there was described a device which included a transducer for measuring the amount of grain lost by the thresher and a transducer for measuring the amount of grain
- 2 - ~
66~
S~Pplied to the hopper, the outputs of the -trclrlsducers being connected to a ratio detector. In the device of Kirk, U.S. Patent 4,00~,28~ there was described a device wherein chaff impinged upon a sensor to provide a signal which 5. passed through two or more band pass filters centred at pre-determined frequencies. In the U.S. Patent 3,935,~66 et al, (assigned to Allis-Chalmers Corporation) there was described a device wherein a monitor derived a grain loss rat~ siynal which was in accordance with the number of grains impinging 10. on a transducer, and this was related to a ground speed signal to provide a reading of percent grain loss per acre.
With all the prior art specified above, and otherwise known to the Applicant, there has been a basic problem which has not been overcome heretofore. Under main circumstances of 15. use, the grain impinging on the sensor is associated with relatively lar~e quantities of chaff or straw, and accurate readings of loss are difficult to achieve. The main object of this invention therefore is to provide a simple grain loss indicator wherein the sensor is more sensitive to the yrain 20. content of discharged discrete material than has been achieved hereto~ore.
BRIEF SUMMARY OF THE INVENTION
Briefly in this invention, there is provided a sensor member which is arranged to be shaken as discrete material 25. is discharged over it. By this means, there is little or no build up of chaff or other discrete material, and con-sequently a clean sensor face is presented to the discrete material (including the discharged grain kernels) as the discrete material passes over the sensor.
More s~ecifically, in one aspect this invention consists of a grain loss indlcator for indicating grain loss from a combine having harvesting means, thresher means, straw walkers, sieves, means to impart fore-and-aft movement to the straw walkers, and means to impart shaking movement to the sieves, comprising: a sheet metal sensor member, mPans securing the sensor member with respect to at least one of the sieves so as to also be subject to said shaking sieve movement, said sensor member being located rearwardly of the sieves and extending across substantially the full width of the sieves so as to lie across substantially the entire path of flow of discrete material as it is discharged over the sieves, an impact detecting transducer carried by and secured with respect to said sensor, electrical readout means, and an electrical signal amplifier electrically interconnecting said transducer and readout means.
Sensor materials which have been used heretofore have frequently employed plastics having a piezo-electric crystal embedded therein or secured thereto. However, I have found that by the use of sheet metal it is possible to have a relatively wide sensor which can extend substantially across the whole of the width of the sieves or the walker and that the sensor can provide accurate readings even when large quantities of straw pass over it. Furthermore, some difriculty is normally encountered with prior art devices in achieving a relatively flat response over the frequency range for various grain kernels, and in another aspect of the invention, a piezo-electric crystal is spaced from but ~i6~1 secured to the sheet metal with a metal stem. I t i.s found that by so mounting the piezo-electric crystal wi-th respect to the sheet metal, an accurate response can be ~chieved over a cange of frequencies which is much broader than that required to identify the grain kernel impact.
In many combine harvesters there is provided a stiffener plate which extends between the side walls of the harvester, which is disposed rearwardly of the straw walkers and which functions as a chute. In another aspect of this invention, a ln. further sensor is a plate-like member which extends across most or all of the width of the straw walkers to thereby lie across the path of discharge of all or nearly all of the flow of discrete material as it is discharged over the straw walkers, and the plate-like member slopes downwardly in a 15. rearward direction, so that it functions as a deflector plate as well as a sensor. Conveniently, the second sensor can be mounted to the stiffening plate if such exists on the combine harvester to which the device is secured.
BRIEF SUMMARY OF THE SEVERAL VIEWS OF THE DRAW~NGS
An embodiment of the invention is described hereunder in some detail with reference to and as illustrated in the accompanying drawings in which:
Fig. 1 is a diagrammatic sectional elevation o~ a combirle harvester, illustrat~ng a first sensor at the discharge end 25. of the sieves, and a second sensor at the discharge end of the straw walker, Fig. 2 is a fra~mentary perspective view which illustrates the mounting of the ~irst sensor on the sieve frame, ;6~l Fig. 3 is a s~:~ctiorlal elevation .illustrating the mounti.nc3 of the secon(i sensor on a plate whic~h extends between the side plates of a combine harvester rearwardly of the straw walkers, 5. Fig. 4 is a section through the first sensor, showing the mounting of the piezo-electric crystal, Fig. 5 is a ~raph which illustrates the frequency imparted to the sensor by various grain kernels, and Fig. 6 is a circuit diagram of the amplifier which 10. interconnects the impact detecting transducer and the readout meter.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring first to Fig. 1, a combine harvester 10 comprises a cutter knife 11 which severs a crop approximately mid way up 15. its stalk, the severed crop being fed into a thresher 12 and transported by a conveyor 13 to a straw walker 14. A first fan 15 blows a draught of air below the straw walker, and a second fan 16 blows a second draught of air through a sieve 17 which comprises three sieve plates 18 carried on a frame 19, the frame 19 being provided with means to cause it to shake.
The straw walker 14 is also provided with means to cause it to move in a fore-and-aft direction. At the rear end of the straw walker 14 there is provided a stiffener plate 20.
Mounted on the aft end and rearwardly of the sieve frame 19 25. is a first sensor 21 containing a piezo~electric transducer 22, and mounted on the stiffener pla-te 20 by means of rubber grommets 23 is a second sensor plate 24 having on it a second piezo-electric transducer 25. Except for the sensors and ~66~1 transducers, the combine harvester lO is one well known in the art, but the invention is equally applicable to other combine harvesters of different construction.
As shown best in Figure 2, the sieve frame l9 has secured to it brackets 30 and -these brackets 30 support the first sensor 21 which comprises a tubular member formed from sheet metal and havin~ closed ends 31, the sensor containing a piezo-electric crystal 22 secured within it and separated from the sheet metal of the sensor by a metal stem 32. The crystal 22 is wired to a terminal 33, and the sheet metal of the first sensor 21 to a second terminal 34, which is merely an earth terminal.
As shown in Figure 3, the stiffener plate 20 has secured to it a second sensor plate 24 by means of the rubber grommets 23, and the second sensor plate 24 carries on it the piezo-electric transducer 25 and, as shown in Figure 3, the transducer 25 is also separated from the plate by a short metal stem. The sensor 25 is wired to a terminal 35, and the sheet metal of the plate 24 to a terminal 36.
The angle of inclination of the second sensor plate is a little less than the angle of inclination of straw being discharged, and the straw is arranged to be deflected only over the lower (downstream) end of the sensor plate, the upper end therefore being free to feel the impact of grain kernels released from the straw as it leaves the straw walkers.
In both instances, the piezo-electric transducer is a 40KHz ceramic crystal manufactured by T.D.K. Electronics of Tokyo, Japan. It is a crystal of the type used for ultra-6~61 sonic transducers. This is found to provide about therequired frequency for a relatively flat response curve (Figure 5) r~, i61 between abollt ] and 20 l~llz.
Both the first sensor 21 (the tubular sievesensor) and the second sensor 24 (the deflector plate straw walker sensor) extend for substantially the full width of respectively the 5. sieves and the straw walkers, and in both instances they are arranged in the path of flow of discrete material discharged respectively from the sieve and straw walker. The precise positioning can best be determined imperically, and will slighly vary with different combine harvesters. However, the first 10. sensor 21 in being continually shaken along with the sieve frame, will always present a relatively clean surface to the grain kernels which impact ayainst it, and it is found that this provides a very accurate reading, and when combined with the sheet metal of the sensor and the stem 32 which connects 15. the sheet metal to the transducer 22, substantial avoidance of errors of reading is achieved.
Fig. 5 illustra~es the approximate frequencies which are imparted to various grains. In ~ig. 5, the abscissa is indicative of frequency and i5 marked in KHz while the 20. ordinate is indicative of signal strength when different frequencies are imparted to the sheet metal of the respective sensors. The dotted line designated 40 at 8KHz indicates the approximate frequency imparted by the wheat kernels impacting against the sensor surface. Similarly, the line 25. 41 designates barley, the line 42 designates oats, the line 43 designates rice and the line 44 designated lucerne (alfalfa) Reference is no~ made to the circuit diagram of Fig. 6.
The circuit is essentially an amplifier generally designated 46 all~l tiliS interconnects the two transducers 22 and 25 to an output reading meter 47. Power is derived from batteries 48, there being two 9 volt packs, one supplying 9 volt negative to ear~n and the other 9 volt positive to earth for 5. two amplifiers, designated respectively 49 and 50, eac~
amplifier being a standard SN741 amplifier which is readily avail~l~le from any one of a number of manufacturers.
Three wires, that is from the sieve transducer 22, the walker transducer 25, and common earth are plugged into the lO. back of the amplifier circuit. A three position two gang rotary switch 51 selects the input to the circuit, by switching in singly the "sieves" transducer or "walkers" transducer, or putting them both in parallel for the intermediate position shown. The impedence of the transducer crystals is very high ~5. and the frequency required to be amplified lies between l and 2~ KHz. The low freguency vibration of the machine, between S0 and 100 !:HZ i~ not required.
The input from t~e transducers into the first amplifier 49 passes through a .47 microfarad capacitor 52 and a l megohm 20. resistor 53 extends between the output side of capacitor 52 and earth, to match roughly the crystal impedence. The first amplifier 49 is a sim~le non-inverting amplifier with a gain of lO. This has a high frequency rolloff of approximately 60KHz. This high f~equency is susceptible to high frequency 25. interference, and a s~all capacitor 54, in series with resistor 55, reduces the frequency rolloff to approximately 25 KHz, and makes the gain of amplifier 49 frequency dependant. The output of the first amplifier 49 passes through a large couplinq c~lpacitor 57 and a resistor 58 into the poten~iometer 59 which corls~ltutes a sensitivity con-trol. The capacitor 57 is utilised ~-o prevent a build~up of direct current output from the amplifier 49.
5. From the sensitivity control potentiometer 59, the signal is fed into the second stage inverting amplifier 50, again a SN741 amplifier. A bank of resistors 61 of differing values provides a range of feedback and therefore a range of amplifier gain. The resistors 61 are selec-ted by a wiper arm of a two 10. gang five position switch 62, and the feed back loop incorporates a capacitor 63 to eliminate direct current gain. The open position on the switch 62 is a readout check position for check-ing the needle deflection of the readout meter 47, and since there is no resistor in the feedback loop there is infinite li. gain. This functions to reveal whether or not the sensors are operating by picking up any movement of any sort of the sensor.
The five position switch also disconnects a low frequency filter choke described hereunder.
The output from the inverting amplifier 50 passes through 20. a large coupling capacitor 64 and resistor 65, this increasing the time constant through the meter so as to damp needle movement. The signal is then passed through the metering circuit which incorporates the diode rectifiers 66 and 67, and a capacitor 68 is placed across this circuit for smoothing 25. purposes.
A 2.5 mH choke 69 bridges the output at the locality of resistor 65 to earth, and therefore filters out machine vibration of lOOHz and less. This circuit is broken ;6~1 however wher- the switch 62 is in the posi-tion shown, which i8 the meter check pOSitiOII.
The swi~ch 70 is a three gang four position switch, which as illustrated can switch in the two ~ volt packs separately, 5. through respective resistors 71, providing means whereby the cell level can be double-checked at any time.
A consideration of the above embodiment will re~eal that the invention provides a nulhber of advantages over prior art.
Eirstly, the first sensor secured to the sieve frame is always 10. kept clean and is responsive to grain impact under severe conditions. SecondlJ~, the flat deflector plate sensor at the discharge end of the walkers is effective because of its size and inclin~tion, and because the discrete material discharged by the walkers must flow over it. The electrical 15. circuit will be seen to provide means for checking sensors at all times, through the switch 62, and finally, as illustrated best in Fig. 5, the circuit of Fig. 6 provides a broad range of control, using only simple amplification techniques. Only very high and very low frequencies are . shunted in thls circuit.
66~
S~Pplied to the hopper, the outputs of the -trclrlsducers being connected to a ratio detector. In the device of Kirk, U.S. Patent 4,00~,28~ there was described a device wherein chaff impinged upon a sensor to provide a signal which 5. passed through two or more band pass filters centred at pre-determined frequencies. In the U.S. Patent 3,935,~66 et al, (assigned to Allis-Chalmers Corporation) there was described a device wherein a monitor derived a grain loss rat~ siynal which was in accordance with the number of grains impinging 10. on a transducer, and this was related to a ground speed signal to provide a reading of percent grain loss per acre.
With all the prior art specified above, and otherwise known to the Applicant, there has been a basic problem which has not been overcome heretofore. Under main circumstances of 15. use, the grain impinging on the sensor is associated with relatively lar~e quantities of chaff or straw, and accurate readings of loss are difficult to achieve. The main object of this invention therefore is to provide a simple grain loss indicator wherein the sensor is more sensitive to the yrain 20. content of discharged discrete material than has been achieved hereto~ore.
BRIEF SUMMARY OF THE INVENTION
Briefly in this invention, there is provided a sensor member which is arranged to be shaken as discrete material 25. is discharged over it. By this means, there is little or no build up of chaff or other discrete material, and con-sequently a clean sensor face is presented to the discrete material (including the discharged grain kernels) as the discrete material passes over the sensor.
More s~ecifically, in one aspect this invention consists of a grain loss indlcator for indicating grain loss from a combine having harvesting means, thresher means, straw walkers, sieves, means to impart fore-and-aft movement to the straw walkers, and means to impart shaking movement to the sieves, comprising: a sheet metal sensor member, mPans securing the sensor member with respect to at least one of the sieves so as to also be subject to said shaking sieve movement, said sensor member being located rearwardly of the sieves and extending across substantially the full width of the sieves so as to lie across substantially the entire path of flow of discrete material as it is discharged over the sieves, an impact detecting transducer carried by and secured with respect to said sensor, electrical readout means, and an electrical signal amplifier electrically interconnecting said transducer and readout means.
Sensor materials which have been used heretofore have frequently employed plastics having a piezo-electric crystal embedded therein or secured thereto. However, I have found that by the use of sheet metal it is possible to have a relatively wide sensor which can extend substantially across the whole of the width of the sieves or the walker and that the sensor can provide accurate readings even when large quantities of straw pass over it. Furthermore, some difriculty is normally encountered with prior art devices in achieving a relatively flat response over the frequency range for various grain kernels, and in another aspect of the invention, a piezo-electric crystal is spaced from but ~i6~1 secured to the sheet metal with a metal stem. I t i.s found that by so mounting the piezo-electric crystal wi-th respect to the sheet metal, an accurate response can be ~chieved over a cange of frequencies which is much broader than that required to identify the grain kernel impact.
In many combine harvesters there is provided a stiffener plate which extends between the side walls of the harvester, which is disposed rearwardly of the straw walkers and which functions as a chute. In another aspect of this invention, a ln. further sensor is a plate-like member which extends across most or all of the width of the straw walkers to thereby lie across the path of discharge of all or nearly all of the flow of discrete material as it is discharged over the straw walkers, and the plate-like member slopes downwardly in a 15. rearward direction, so that it functions as a deflector plate as well as a sensor. Conveniently, the second sensor can be mounted to the stiffening plate if such exists on the combine harvester to which the device is secured.
BRIEF SUMMARY OF THE SEVERAL VIEWS OF THE DRAW~NGS
An embodiment of the invention is described hereunder in some detail with reference to and as illustrated in the accompanying drawings in which:
Fig. 1 is a diagrammatic sectional elevation o~ a combirle harvester, illustrat~ng a first sensor at the discharge end 25. of the sieves, and a second sensor at the discharge end of the straw walker, Fig. 2 is a fra~mentary perspective view which illustrates the mounting of the ~irst sensor on the sieve frame, ;6~l Fig. 3 is a s~:~ctiorlal elevation .illustrating the mounti.nc3 of the secon(i sensor on a plate whic~h extends between the side plates of a combine harvester rearwardly of the straw walkers, 5. Fig. 4 is a section through the first sensor, showing the mounting of the piezo-electric crystal, Fig. 5 is a ~raph which illustrates the frequency imparted to the sensor by various grain kernels, and Fig. 6 is a circuit diagram of the amplifier which 10. interconnects the impact detecting transducer and the readout meter.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring first to Fig. 1, a combine harvester 10 comprises a cutter knife 11 which severs a crop approximately mid way up 15. its stalk, the severed crop being fed into a thresher 12 and transported by a conveyor 13 to a straw walker 14. A first fan 15 blows a draught of air below the straw walker, and a second fan 16 blows a second draught of air through a sieve 17 which comprises three sieve plates 18 carried on a frame 19, the frame 19 being provided with means to cause it to shake.
The straw walker 14 is also provided with means to cause it to move in a fore-and-aft direction. At the rear end of the straw walker 14 there is provided a stiffener plate 20.
Mounted on the aft end and rearwardly of the sieve frame 19 25. is a first sensor 21 containing a piezo~electric transducer 22, and mounted on the stiffener pla-te 20 by means of rubber grommets 23 is a second sensor plate 24 having on it a second piezo-electric transducer 25. Except for the sensors and ~66~1 transducers, the combine harvester lO is one well known in the art, but the invention is equally applicable to other combine harvesters of different construction.
As shown best in Figure 2, the sieve frame l9 has secured to it brackets 30 and -these brackets 30 support the first sensor 21 which comprises a tubular member formed from sheet metal and havin~ closed ends 31, the sensor containing a piezo-electric crystal 22 secured within it and separated from the sheet metal of the sensor by a metal stem 32. The crystal 22 is wired to a terminal 33, and the sheet metal of the first sensor 21 to a second terminal 34, which is merely an earth terminal.
As shown in Figure 3, the stiffener plate 20 has secured to it a second sensor plate 24 by means of the rubber grommets 23, and the second sensor plate 24 carries on it the piezo-electric transducer 25 and, as shown in Figure 3, the transducer 25 is also separated from the plate by a short metal stem. The sensor 25 is wired to a terminal 35, and the sheet metal of the plate 24 to a terminal 36.
The angle of inclination of the second sensor plate is a little less than the angle of inclination of straw being discharged, and the straw is arranged to be deflected only over the lower (downstream) end of the sensor plate, the upper end therefore being free to feel the impact of grain kernels released from the straw as it leaves the straw walkers.
In both instances, the piezo-electric transducer is a 40KHz ceramic crystal manufactured by T.D.K. Electronics of Tokyo, Japan. It is a crystal of the type used for ultra-6~61 sonic transducers. This is found to provide about therequired frequency for a relatively flat response curve (Figure 5) r~, i61 between abollt ] and 20 l~llz.
Both the first sensor 21 (the tubular sievesensor) and the second sensor 24 (the deflector plate straw walker sensor) extend for substantially the full width of respectively the 5. sieves and the straw walkers, and in both instances they are arranged in the path of flow of discrete material discharged respectively from the sieve and straw walker. The precise positioning can best be determined imperically, and will slighly vary with different combine harvesters. However, the first 10. sensor 21 in being continually shaken along with the sieve frame, will always present a relatively clean surface to the grain kernels which impact ayainst it, and it is found that this provides a very accurate reading, and when combined with the sheet metal of the sensor and the stem 32 which connects 15. the sheet metal to the transducer 22, substantial avoidance of errors of reading is achieved.
Fig. 5 illustra~es the approximate frequencies which are imparted to various grains. In ~ig. 5, the abscissa is indicative of frequency and i5 marked in KHz while the 20. ordinate is indicative of signal strength when different frequencies are imparted to the sheet metal of the respective sensors. The dotted line designated 40 at 8KHz indicates the approximate frequency imparted by the wheat kernels impacting against the sensor surface. Similarly, the line 25. 41 designates barley, the line 42 designates oats, the line 43 designates rice and the line 44 designated lucerne (alfalfa) Reference is no~ made to the circuit diagram of Fig. 6.
The circuit is essentially an amplifier generally designated 46 all~l tiliS interconnects the two transducers 22 and 25 to an output reading meter 47. Power is derived from batteries 48, there being two 9 volt packs, one supplying 9 volt negative to ear~n and the other 9 volt positive to earth for 5. two amplifiers, designated respectively 49 and 50, eac~
amplifier being a standard SN741 amplifier which is readily avail~l~le from any one of a number of manufacturers.
Three wires, that is from the sieve transducer 22, the walker transducer 25, and common earth are plugged into the lO. back of the amplifier circuit. A three position two gang rotary switch 51 selects the input to the circuit, by switching in singly the "sieves" transducer or "walkers" transducer, or putting them both in parallel for the intermediate position shown. The impedence of the transducer crystals is very high ~5. and the frequency required to be amplified lies between l and 2~ KHz. The low freguency vibration of the machine, between S0 and 100 !:HZ i~ not required.
The input from t~e transducers into the first amplifier 49 passes through a .47 microfarad capacitor 52 and a l megohm 20. resistor 53 extends between the output side of capacitor 52 and earth, to match roughly the crystal impedence. The first amplifier 49 is a sim~le non-inverting amplifier with a gain of lO. This has a high frequency rolloff of approximately 60KHz. This high f~equency is susceptible to high frequency 25. interference, and a s~all capacitor 54, in series with resistor 55, reduces the frequency rolloff to approximately 25 KHz, and makes the gain of amplifier 49 frequency dependant. The output of the first amplifier 49 passes through a large couplinq c~lpacitor 57 and a resistor 58 into the poten~iometer 59 which corls~ltutes a sensitivity con-trol. The capacitor 57 is utilised ~-o prevent a build~up of direct current output from the amplifier 49.
5. From the sensitivity control potentiometer 59, the signal is fed into the second stage inverting amplifier 50, again a SN741 amplifier. A bank of resistors 61 of differing values provides a range of feedback and therefore a range of amplifier gain. The resistors 61 are selec-ted by a wiper arm of a two 10. gang five position switch 62, and the feed back loop incorporates a capacitor 63 to eliminate direct current gain. The open position on the switch 62 is a readout check position for check-ing the needle deflection of the readout meter 47, and since there is no resistor in the feedback loop there is infinite li. gain. This functions to reveal whether or not the sensors are operating by picking up any movement of any sort of the sensor.
The five position switch also disconnects a low frequency filter choke described hereunder.
The output from the inverting amplifier 50 passes through 20. a large coupling capacitor 64 and resistor 65, this increasing the time constant through the meter so as to damp needle movement. The signal is then passed through the metering circuit which incorporates the diode rectifiers 66 and 67, and a capacitor 68 is placed across this circuit for smoothing 25. purposes.
A 2.5 mH choke 69 bridges the output at the locality of resistor 65 to earth, and therefore filters out machine vibration of lOOHz and less. This circuit is broken ;6~1 however wher- the switch 62 is in the posi-tion shown, which i8 the meter check pOSitiOII.
The swi~ch 70 is a three gang four position switch, which as illustrated can switch in the two ~ volt packs separately, 5. through respective resistors 71, providing means whereby the cell level can be double-checked at any time.
A consideration of the above embodiment will re~eal that the invention provides a nulhber of advantages over prior art.
Eirstly, the first sensor secured to the sieve frame is always 10. kept clean and is responsive to grain impact under severe conditions. SecondlJ~, the flat deflector plate sensor at the discharge end of the walkers is effective because of its size and inclin~tion, and because the discrete material discharged by the walkers must flow over it. The electrical 15. circuit will be seen to provide means for checking sensors at all times, through the switch 62, and finally, as illustrated best in Fig. 5, the circuit of Fig. 6 provides a broad range of control, using only simple amplification techniques. Only very high and very low frequencies are . shunted in thls circuit.
Claims (8)
1. Grain loss indicator for indicating grain loss from a combine having harvesting means, thresher means, straw walkers, sieves, means to impart fore-and-aft movement to the straw walkers, and means to impart shaking movement to the sieves, comprising:
a sheet metal sensor member, means securing the sensor member with respect to at least one of the sieves so as to also be subject to said shaking sieve movement, said sensor member being located rearwardly of the sieves and extending across substantially the full width of the sieves so as to lie across substantially the entire path of flow of discrete material as it is discharged over the sieves, an impact detecting transducer carried by and secured with respect to said sensor, electrical readout means, and two electrical signal amplifiers electrically inter-connecting said transducer and readout means.
a sheet metal sensor member, means securing the sensor member with respect to at least one of the sieves so as to also be subject to said shaking sieve movement, said sensor member being located rearwardly of the sieves and extending across substantially the full width of the sieves so as to lie across substantially the entire path of flow of discrete material as it is discharged over the sieves, an impact detecting transducer carried by and secured with respect to said sensor, electrical readout means, and two electrical signal amplifiers electrically inter-connecting said transducer and readout means.
2. Grain loss indicator according to claim 1 wherein the impact detecting transducer comprises a piezo-electric crystal spaced from but secured to said sheet metal of the sensor with a metal stem, the stem being of substantially smaller size than the crystal.
3. Grain loss indicator according to claim 1 or claim 2 wherein said sensor member comprises a tube of sheet metal having an interior wall, and means securing the impact detecting transducer to the interior wall of the tube so that the transducer lies wholly within the tube.
4. Grain loss indicator according to claim 1 corn-prising a further sensor member positioned rearwardly of the straw walker and lying across the path of flow of discrete material as it is discharged from the straw walker, and a further impact detecting transducer carried by and secured with respect to said further sensor, said further sensor being a plate-like member which extends across substantially the full width of the straw walkers and lies across sub-stantially the entire path of flow of discrete material as the discrete material is discharged over the straw walkers, said plate-like member sloping downwardly in a rearward direction with respect to the walker.
5. Grain loss indicator for indicating grain loss from a combine having harvesting means, thresher means, straw walkers, sieves, means to impart fore-and-aft move-ment to the straw walkers, and shaking means to impart shaking movement to the sieves, comprising:
a first sensor member located rearwardly of the sieves extending across the path of flow of discrete material as it is discharged from the sieves, and means connecting the first sensor member to said shaking means so as to effect shaking movement of the sensor member when the sieves are shaken, a second sensor member located rearwardly of the straw walker and extending across the path of flow of straw as it is discharged from the straw walker, each said sensor member comprising sheet metal, a piezo-electric crystal, and a metal stem between the sheet metal of each sensor and its respective crystal securing the crystal to the sheet metal to be responsive to impact vibrations imparted to the sheet metal, the stem being of substantially smaller size than the crystal;
a signal readout meter, an amplifier circuit inter-connecting the piezo-electric crystals and the readout meter, and high and low frequency filters in the amplifier circuit effective to remove signals above 25 KHz and below 100 Hz.
a first sensor member located rearwardly of the sieves extending across the path of flow of discrete material as it is discharged from the sieves, and means connecting the first sensor member to said shaking means so as to effect shaking movement of the sensor member when the sieves are shaken, a second sensor member located rearwardly of the straw walker and extending across the path of flow of straw as it is discharged from the straw walker, each said sensor member comprising sheet metal, a piezo-electric crystal, and a metal stem between the sheet metal of each sensor and its respective crystal securing the crystal to the sheet metal to be responsive to impact vibrations imparted to the sheet metal, the stem being of substantially smaller size than the crystal;
a signal readout meter, an amplifier circuit inter-connecting the piezo-electric crystals and the readout meter, and high and low frequency filters in the amplifier circuit effective to remove signals above 25 KHz and below 100 Hz.
6. Grain loss indicator according to claim 5 wherein said second sensor member is a sheet metal plate which slopes downwardly and rearwardly of said straw walker at a less inclined angle than said path of flow of straw when discharged from the straw walker such that the straw is deflected by the lower and rear end of said second sensor but some at least of said second sensor plate is suffi-ciently clear of straw to be responsive to impact of grain kernels released from straw as it leaves the straw walkers.
7. Grain loss indicator according to claim 5 wherein said amplifier circuit comprises two amplifiers in tandem, and a sensitivity control variable resistor is interposed between the output of the first said amplifier and the input of the second said amplifier.
8. Grain loss indicator according to claim 7 wherein the second said amplifier comprises a bank of feedback resistors of differing values which provide a range of amplifier gain, and a multi-position switch selectively placing said feed back resistors into circuit, said multi-position switch having an open circuit position at which said second amplifier has infinite gain, thereby constitu-ting readout check means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPD127677 | 1977-08-17 | ||
| AUPD1276 | 1977-08-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1146661A true CA1146661A (en) | 1983-05-17 |
Family
ID=3767132
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000307242A Expired CA1146661A (en) | 1977-08-17 | 1978-07-12 | Grain loss indicator having a sensor member secured to a shaken with a sieve frame |
Country Status (6)
| Country | Link |
|---|---|
| AR (1) | AR219538A1 (en) |
| CA (1) | CA1146661A (en) |
| DE (1) | DE2835895A1 (en) |
| FR (1) | FR2400319A1 (en) |
| GB (1) | GB2002903B (en) |
| IT (1) | IT1105924B (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4230130A (en) * | 1979-02-05 | 1980-10-28 | International Harvester Company | Combine grain loss sensing |
| US4275546A (en) * | 1980-01-04 | 1981-06-30 | Sperry Corporation | Stone discriminator |
| GB8305219D0 (en) * | 1983-02-25 | 1983-03-30 | Sperry Nv | Combine harvesters |
| DE3731080A1 (en) * | 1987-09-16 | 1989-03-30 | Claas Ohg | LOSS GRAIN SENSOR FOR HARVESTING MACHINES |
| DE3733619A1 (en) * | 1987-10-05 | 1989-04-13 | Deere & Co | METHOD FOR EVENLY DISTRIBUTING A GOOD TO BE SEPARATED IN A SEPARATING DEVICE AND MEANS OF ITS DESIGN |
| EP0339140B1 (en) * | 1988-04-26 | 1993-09-29 | New Holland Belgium N.V. | Grain loss monitors for harvesting machines |
| US5046362A (en) * | 1988-04-26 | 1991-09-10 | Ford New Holland, Inc. | Grain loss monitors for harvesting machines |
| DE3874325T2 (en) * | 1988-04-26 | 1993-02-25 | Ford New Holland Inc | IMPACT DETECTORS. |
| DD289191A5 (en) * | 1989-11-28 | 1991-04-25 | Saechsische Maehdrescherwerke Ag,De | SENSOR FOR AGRICULTURAL MACHINES |
| DD289685A5 (en) * | 1989-11-28 | 1991-05-08 | Saechsische Maehdrescherwerke Ag,De | DEVICE FOR COLLECTING THE RESOURCE PURCHASE |
| DE19725028A1 (en) * | 1997-06-13 | 1998-12-17 | Claas Selbstfahr Erntemasch | Harvester sensor |
| US6431981B1 (en) | 1999-06-30 | 2002-08-13 | Wisconsin Alumni Research Foundation | Yield monitor for forage crops |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1270535A (en) * | 1968-03-06 | 1972-04-12 | Massey Ferguson Perkins Ltd | Improvements in or relating to combine harvesters |
| US3606745A (en) * | 1969-09-08 | 1971-09-21 | Massey Ferguson Ind Ltd | Grain flow rate monitor |
| US3939846A (en) * | 1974-06-27 | 1976-02-24 | Vladimir Kirillovich Drozhzhin | Device for monitoring and controlling the relative flows and losses of grain in a grain combine thresher |
| US3935866A (en) * | 1974-12-23 | 1976-02-03 | Allis-Chalmers Corporation | Grain loss monitor |
| GB1468477A (en) * | 1975-08-18 | 1977-03-30 | Rds Ltd | Comine-harvester provided with grain sensing means |
| US4004289A (en) * | 1975-12-17 | 1977-01-18 | Canadian Patents And Development Limited | Acoustic grain flow rate monitor |
-
1978
- 1978-07-12 CA CA000307242A patent/CA1146661A/en not_active Expired
- 1978-07-21 IT IT50418/78A patent/IT1105924B/en active
- 1978-07-27 AR AR273102A patent/AR219538A1/en active
- 1978-08-02 GB GB7831923A patent/GB2002903B/en not_active Expired
- 1978-08-16 DE DE19782835895 patent/DE2835895A1/en active Granted
- 1978-08-17 FR FR7823982A patent/FR2400319A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| DE2835895C2 (en) | 1988-03-24 |
| IT1105924B (en) | 1985-11-11 |
| FR2400319A1 (en) | 1979-03-16 |
| AR219538A1 (en) | 1980-08-29 |
| GB2002903B (en) | 1982-03-03 |
| IT7850418A0 (en) | 1978-07-21 |
| GB2002903A (en) | 1979-02-28 |
| DE2835895A1 (en) | 1979-03-01 |
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| MKEX | Expiry |