Method and apparatus for adjusting a shear bar relative to a cutter head

Abstract

Under the control of a microprocessor first and second motors alternately drive first and second ends of a shear bar for adjusting the position of the shear bar relative to cutter head. The shear bar is adjusted so that it is substantially parallel to the cutter head even though the cutter head and shear bar may not be parallel at the time the adjustment is initiated. A knock sensor is provided for sensing impacts between the cutter head and shear bar, the knock sensor output signal being converted to a digital value for controlling the adjusting sequence. A knocker is provided for inducing vibrations in the shear bar to thereby test the operability of the knock sensor and its output circuitry. The sensitivity of the adjustment system to the output of the knock sensor is set automatically before an adjustment sequence begins to account for variations in the knock sensor, its output circuitry, and "noise" vibrations induced in the shear bar by normal machine operation.

Description

digital value. At step 1212, this value is compared with the value of NOI2 obtained during execution of GETNOI at step 1205. If the knock sensor ouptut value is greater than NOI2 it indicates that the cutter head is hitting the shear bar so the program branches to FIG. 12C.

Assuming that the sensor output value is less than NOI2, no hit has occurred so the program proceeds from step 1212 to step 1213 where the motor current value obtained during the last execution of the NMIR routine is compared to a value representing the maximum allowable current. If the motor current does not exceed the maximum allowable value then at step 1215 it is compared with a value representing the minimum allowable current. It may be noted that steps 1213-1222 of the ADJUST routine correspond exactly with steps 1107-1113, 1120-1122 and 1130-1132 of the PULOUT subroutine described above.

If the checks of the motor current show that it is within the prescribed limits then at step 1224 the EOTIN flag is checked to see if the motor has driven the end of the shear bar to its inward limit of travel. If it has not, the RPMOK flag is checked to see if the cutter head is still rotating. Assuming it is, QSEC is decremented at 1226 and then tested at 1227 to see if 1/4 second has elapsed.

If the test at step 1227 shows that 1/4 second has not elapsed then the program loops back to step 1211 and repeats the loop comprising steps 1211-1216 and 1224-1227. When 1/4 second has elapsed the test at step 1227 proves true and the program moves to step 1228 where it resets QSEC to time another quarter-second interval and decrements ONTIME, the number of quarter second intervals that the rooter is to be on. In a typical system ONTIME may be about 10.

After ONTIME is decremented it is tested at step 1229 to see if the motor energizing interval has expired. If it has not, the program loops back to step 1211. If the energizing interval has expired the program moves to step 1262 (FIG. 12C) where the flags IMP1, IMP2 and HITFLAG are cleared. The program then proceeds to step 1230 (FIG. 12D) where the microprocessor sends a code to VIA 208 which terminates the output signal for energizing relay K2. When relay K2 opens motor M1 stops. A jump is then made to the TSTGEN subroutine to check the operation of the knock sensor before beginning the movement of the other motor. Upon the return from TSTGEN the location WICHMO is tested to see if M1 or M2 was the motor whose movement was just completed. If WICHMO indicates M1 then at step 1233 it is set to indicate M2 and the code is obtained for controlling M2 to move the shear bar inwardly toward the cutter head. On the other hand, if the test at step 1232 should indicate that WICHMO is set to M2 then at step 1234 it is set to indicate M1 and a code is obtained for controlling M1 to move the shear inwardly. After completion of step 1233 or 1234 the program branches back to step 1207 (FIG. 12A) where the code obtained at step 1233 or 1234 is sent to VIA 208 to energize either relay K2 or K4 and thereby activate motor M1 or M2 to move its end of the shear bar inwardly toward the cutter head.

Depending on the position of the shear bar at the time the adjusting procedure is initiated, M1 and M2, may be alternately energized one or more times as described above without driving either end of the shear bar into contact with the rotating cutter bar. Eventually however energization of one of the motors will result in contact. When RDSENS is executed at step 1211 to read the knock sensor output, this output will be larger than NOI2. Therefore, when the knock sensor output is compared to NOI2 at step 1212 the program recognizes the hit and branches to step 1240 (FIG. 12C) where a code is sent to VIA 208 which deenergizes all relays K2-K5 thereby stopping all motors. At step 1241 WICHMO is checked to see which motor caused the hit. If it was M1 then the flag IMP1 is set at step 1242. IMP1 and IMP2 are checked at step 1243 to see if both have been set. If both IMP1 and IMP2 are set then HITFLG is set at 1244 before step 1245 is executed. If IMP1 and IMP2 are not both set then the program branches from step 1243 to 1245.

At step 1245 the flag POUTF is cleared, the code for moving M1 outwardly is fetched to the microprocessor A register and BOUT, the number of quarter-second intervals the motor is to be energized, is loaded into the microprocessor X register. BOUT may be on the order of 5. A jump is then made to the PULOUT subroutine to energize M1 in a direction to move the shear bar away from the cutter head.

Upon return from the PULOUT subroutine HITFLG is tested. If it is not set, i.e. there hasn't been at least one impact by each of the motors, the program moves to step 1248 where the TSTGEN subroutine is executed to test the knock sensor. At step 1249 WICHMO is set to indicate M2, QSEC is reset to time a quarter-second interval, and the code is obtained for controlling the motor M2 to move the shear bar inwardly. The program then branches back to step 1207 where the motor is turned on by sending the code to the VIA 208.

Returning to step 1241, if the test shows that WICHMO is set to indicate M2 then the program branches to step 1252. Steps 1252-1259 correspond to steps 1242-1249 the only differences being that the flag IMP2 is set at step 1252, the code for energizing M2 is obtained at step 1255, and WICHMO is set to M1 and the code for energizing M1 is obtained at step 1259.

If a test at step 1147 or 1257 shows that HITFLG is set, the program then decrements TIMS at 1260 and tests it at 1261. If TIMS is not zero the program branches to 1262 to clear IMP1, IMP2 and HITFLG in preparation for checking for another set of impacts, one by each end of the shear bar. It then proceeds to FIG. 12D where the state of WICHMO is changed and the code for next energizing one of the motors is obtained before branching back to step 1270 to energize the motor.

If the test at step 1261 proves true it means that the adjusting sequence is complete. A flag is set at step 1263 to beep the alarm 286, and the program then jumps to the READY rotine.

It has been found that after two "hits", i.e. after pacts have twice caused HITFLG to be set, the shear bar is spaced on the order of 0.005 to 0.010 inch from the cutter head and essentially parallel thereto. The gap between the shear bar and the cutter head at the end of the adjusting procedure is governed in large part by the value of BOUT at step 1245 or 1255 which in turn controls the duration of motor energization during the PULOUT subroutines at steps 1247 1246 and 1248 1256.

If the test at step 1201 or 1224 shows that the EOTIN flag is set, it means that one of the end of travel switches 258 or 260 is actuated because one end of the shear bar has been moved to its limit of travel toward the cutter head. In this case the program sets flags to turn on one of the indicators 314 to indicate EOT and sound an alarm, and then jumps to the ALARM routine. In like manner, if the RPMOK flag is not set when the test is made at step 1225, the programs sets appropriate flags to turn on the RPM indicator and the alarm, and jumps to the ALARM routine.

At step 1202, the RPMOK flag is tested prior to any motor actuation. If the flag is not set the program sets flags for giving the alarm indication and at step 1281 tests the QUIT flag to see if the operator has depressed the Quit switch. If he has, the program jumps to the ready routine. If he has not, a Wait for Interrupt is executed during the wait. The program then branches back to step 1202 to again check the RPMOK flag. If the cutter head is up to speed the program then clears the alarm flags at step 1203.

It will be recognized by those skilled in the art that by properly programming the VIA 208 so that some bus bit positions alternately serve as input or output, it would be possible to completely dispense with the PIA 206. Thus, there is wide latitude in programming the control of the various indicators and alarms. For this reason the ALARM routine is not specifically described. The PIA 206 becomes necessary only when additional control features such as an automatic knife sharpener control arc added into the system.

PULFOUT Routine

As previously indicated, the PULSW flag is set if the Quit and Adjust switches are actuated concurrently. By actuating both switches the operator may initiate the PULFOUT routine which moves each end of the shear bar to its limit of travel away from the cutter head.

If the test at step 708 shows that PULSW is set the program jumps to the PULFOUT routine shown in FIG. 13. At step 1300 the Busy and POUTF flags are set, the length of time for energizing the motor is loaded in the microprocessor X register, and the code for energizing M1 to move the shear bar outwardly is entered in the A register. The program then jumps to the PULOUT subroutine to energize M1. Upon the return to PULFOUT EOTOUT1 is tested to see if end A of the shear bar is at its limit of travel If not, the QUIT flag is tested at 1303. Assuming the Quit switch has not been actuated by the operator the microprocessor gets the control values for moving motor M2 outwardly (step 1304) and executes the PULOUT subroutine at step 1305 to move end B of the shear bar. Step 1306 tests EOTOUT2 to see if end B of the shear bar is at its limit of travel and if it is not the QUIT flag is tested at step 1307.

If the Quit switch is not depressed the program branches back to the beginning of the subroutine and continues executing the steps described above. When end A of the shear bar reaches its outward limit of travel the test at 1302 proves true and the program branches to turn off the motor (step 1308) and set the flag for beeping the alarm (step 1309). The program then jumps to the READY routine. The program also branches to step 1308 if the test at step 1306 indicates that end B of the shear bar is at its outward limit of travel.

The PULFOUT subroutine may be halted by depressing the Quit switch alone. The sets the QUIT flag so that the program will branch from step 1303 or 1307 to step 1308, thus ending the pullout operation.

In summary, the present invention provides a completely automatic control for adjusting the position of a shear bar relative to a routing cutter head by alternately energizing first one and then the other motor to alternately move first one end of the shear bar and then the other. The system includes a knocker for inducing vibrations into the shear bar so that the operability of the knock sensor and its associated circuitry may be automatically checked. The system also automatically checks "noise" vibrations in the shear bar and adjusts the sensitivity of the system to the output signal from the knock sensor.

While a specific preferred embodiment of the invention has been described in detail, various modifications and substitutions may be made in the described embodiment without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. In a cutting apparatus having an adjustably fixed shear bar cooperating with a rotating cutter head to cut material passing between the bar and head, the improvement comprising:

first and second bidirectional motors;

first means responsive to said first motor for moving a first end of said shear bar relative to said cutter head;

second means responsive to said second motor for moving a second end of said shear bar relative to said cutter head;

sensing means for sensing contact between said shear bar and said cutter head;

start control means; and,

electrical control means responsive to said start control means and said sensing means for controlling said first and second motors to adjust the position of said shear bar,

said electrical control means including means for alternately energizing one of said motors and then the other whereby one end and then the other end of said shear bar is moved until said shear bar is adjusted relative to said cutter head.

2. The improvement as claimed in claim 1 wherein said sensing means comprises a vibration sensor mounted on a support bar which also supports said shear bar.

3. The improvement as claimed in claim 1 wherein said shear bar is longer than the width of said cutter head.

4. The improvement as claimed in claim 1 wherein said electrical control means comprises a microprocessor, a memory, an analog to digital converter, an interface adapter interconnected by bus means, said sensing means being connected to said analog to digital converter, and means connected to said interface adapter for energizing and controlling the direction of rotation of said motors in accordance with signals applied by said sensing means to said analog to digital converter and a program executed by said microprocessor.

5. The improvement as claimed in claim 4 wherein said electrical control means includes means for sensing the magnitude of current flowing through said motors and deenergizing said motors if said magnitude falls above or below a predetermined range for a predetermined interval of time.

6. The improvement as claimed in claim 4 wherein said electrical control means includes sensing the rate of rotation of said cutter head and deenergizing said motors if said rate of rotation is less than a predetermined minimum rate.

7. The improvement as claimed in claim 1 and further comprising test signal generator means responsive to said electrical control means for inducing vibrations in said shear bar which may be sensed by said sensing means to determine the operability of said sensing means.

8. A method of adjusting the position of a shear bar relative to a rotating cutter head in a cutting apparatus having an adjustably fixed shear bar cooperating with a rotating cutter head to cut material passing between the bar and head, and first and second bidirectional motors connected to move first and second ends of said shear bar, said method comprising the steps of:

energizing said first motor to move a first end of said shear bar toward said head for a fixed interval of time or until it contacts said cutter head and then energizing said first motor to move said first end away from said cutter head a predetermined distance,

deenergizing said first motor;

energizing said second motor to move a second end of said shear bar toward said cutter head for a fixed interval of time or until it contacts said cutter head and then energizing said second motor to move said second end away from said cutter head said predetermined distance;

deenergizing said second motor; and

repeating each of the preceding steps until said first and second ends of said shear bar each contacts said cutter head on each of two separate energizations of the respective motors which move said ends.

9. The method as claimed in claim 8 wherein contact between said shear bar and said cutter head is determined by sensing vibrations in said shear bar.

10. The method as claimed in claim 8 wherein, prior to energizing either motor to move the shear bar toward the cutter, each motor is energized for a fixed interval of time to move the shear bar away from the

cutter head. 11. In a cutting apparatus having an adjustably fixed shear bar cooperating with a rotating cutter head to cut material passing between the bar and head, and a vibration sensor for sensing contact between said bar and head, the improvement comprising:

first means for inducing vibrations in said shear bar which may be sensed by said vibration sensor;

an analog to digital converter responsive to said vibration sensor for producing a digital value indicative of the magnitude of output signals produced by said vibration sensor in response to vibrations in said shear bar;

indicator means; and,

microprocessor controlled means for energizing said first means to induce said vibrations, comparing said digital value to a reference value, and energizing said indicator means if said digital value is less than said

reference value. 12. In a cutting apparatus having an adjustably fixed shear bar cooperating with a rotating cutter head to cut material passing between the bar and head, the improvement comprising:

vibration sensing means for sensing vibrations in said shear bar;

analog to digital converter means responsive to said sensing means for producing a digital value indicative of the magnitude of vibrations in said shear bar;

motor means for selectively moving said shear bar toward or away from said cutter head; and,

sequence control means for selectively energizing said motor means to move said shear bar away from said cutter head, sensing said digital value and adding a reference value thereto to obtain a sensitivity level value, moving said shear bar toward said cutter head while sampling said digital value for evidence of contact between said shear bar and cutter head, and stopping movement of said shear bar toward said cutter head when said

sampled digital value exceeds said sensitivity level value. 13. In a forage harvester having a pair of members for processing material introduced therebetween, and an adjustment mechanism for adjusting clearance between the members, a control system cooperating with the adjustment mechanism for automatically adjusting clearance between the members, characterized by:

a rotation sensor for sensing rotation of one of the members, and

means responsive to the rotation sensor for preventing adjustment of the clearance between the members if the rotation speed of the one member is outside of a certain range. 14. In a material processing machine having a pair of members for processing material introduced therebetween, a mechanism for moving one of the members towards and away from the other member and a control system cooperating with the mechanism to automatically adjust clearance between the members, characterized by:

the control system including means for automatically moving the one member towards the other member; and

means for automatically stopping movement of the one member if the one member moving mechanism operates for at least a certain time period without engagement between the members,

said means for automatically stopping movement of the one member comprising a counter, means for setting said counter to a first predetermined value, means for modifying the value in said counter at fixed intervals of time while said one member is moving toward said other member, and means responsive to said counter when it contains a second predetermined value for deenergizing the means for automatically moving said one member towards the other member. 15. The invention of claim 14, wherein the control system further comprises:

means for automatically moving the one member a certain distance away from the other member after the one member engages the other member. 16. The invention of claim 14 wherein the control system further comprises:

an operator-observable display device; and

means for causing the display device to provide an indication of movement

of the one member. 17. The invention of claim 14, further comprising:

means for automatically stopping movement of the one member when the one member engages the other member. 18. The invention of claim 14, wherein:

the mechanism comprises a first adjuster connected to a first end of the one member and a second adjuster connected to a second end of the one member; and

the control system cooperates with the adjusters to perform an automatic adjustment by:

a) moving the first end of the one member a certain distance towards the other member, then stopping movement of said first end;

b) moving the second end of the one member a certain distance towards the other member, then stopping movement of said second end; and

c) repeating steps a) and b) until an end of the one member engages the

other member. 19. In the forage harvester of claim 13, wherein said one member comprises a rotating cutterhead, and wherein the other member comprises an adjustably mounted shearbar. 20. In the forage harvester of claim 13, wherein said rotation sensor comprises a tachometer. 21. In the forage harvester of claim 13, wherein said adjustment preventing means comprises an electrical control circuit. 22. In the forage harvester of claim 13, wherein said certain range is equal to or greater than a preselected minimum speed. 23. The invention of claim 14, wherein said means for automatically moving the one member comprises a motor.

24. The invention of claim 14, wherein said one member comprises an adjustable mounted shearbar, and wherein said other member comprises a rotating cutterhead. 25. The invention of claim 15, wherein said means for automatically moving the one member a certain distance away from the other member comprises detector means for detecting engagement between said one member and said other member, a motor energizable for moving said one member; a counter; means responsive to said detector means for setting said counter to a first predetermined value; means for modifying the value in said counter at fixed intervals of time; and means responsive to said counter when it contains a second predetermined value for deenergizing said motor. 26. The invention of claim 16, wherein said control system comprises a microprocessor and said means for causing the display device to provide an indication of movement of said one member as it initiates movement of said one member towards said other member. 27. The invention of claim 17, wherein said means for moving said one member towards said other member includes a motor and said means for automatically stopping movement comprises detector means for detecting engagement of said one member with said other member and means responsive to said detector means for deenergizing said motor. 28. In a cutting apparatus having an adjustably fixed shear bar cooperating with a rotating cutter head to cut material passing between the bar and head, the improvement comprising:

first and second bidirectional motors;

first means responsive to said first motor for moving a first end of said shear bar relative to said cutter had;

second means responsive to said second motor for moving a second end of said shear bar relative to said cutter head;

sensing means for sensing contact between said shear bar and said cutter head;

start control means, and,

electrical control means responsive to said start control means and said sensing means for controlling said first and second motors to adjust the position of said shear bar,

said electrical control means including means for alternately energizing one of said motors and then the other whereby one end and then the other end of said shear bar is moved until said shear bar is adjusted relative to said cutter head,

wherein said electrical control means comprises a microprocessor, a memory, an analog to digital converter, an interface adapter interconnected by bus means, said sensing means being connected to said analog to digital converter, and means connected to said interface adapter for energizing and controlling the direction of rotation of said motors in accordance with signals applied by said sensing means to said analog to digital converter and a program executed by said microprocessor,

wherein said electrical control means includes means for sensing the rate of rotation of said cutter head and deenergizing said motors if said rate of rotation is less than a predetermined minimum rate.