Claims
- 1. An apparatus for forming concrete pipe of uniform density comprising:
- (a) means for forming concrete into the form of said pipe comprising a mold having an inner wall, a packing head for packing concrete against said inner wall, a shaft centrally mounted on said packing head, a packing head motor for revolving said packing head through the mold and means for raising said packing head only at a fixed rate and for lowering said packing head in at least one pass;
- (b) means for feeding concrete to said forming means;
- (c) a feed motor for driving said concrete feeding means;
- (d) means for sensing and measuring the components of the actual power being used by said packing head motor said power being a function of torque generated in said packing head;
- (e) means for selecting a desired power;
- (f) means for comparing said actual power to said desired power; and
- (g) means for controlling the speed of said feed motor responsive to said means for comparing.
- 2. Apparatus according to claim 1 wherein said means for sensing and measuring comprises means for sensing and measuring the components of horsepower.
- 3. Apparatus according to claim 1 wherein said means for controlling speed comprises a regenerative speed control.
- 4. A control system for use with apparatus for making a concrete pipe, said apparatus including a mold; a conveyor for feeding concrete to said mold; a motor for driving said conveyor; a packing head for rotating within said mold to distribute and pack concrete supplied by said conveyor; a drive motor for driving said packing head; and means for controllably raising and lower said packing head in first and second passes, comprising:
- (a) a speed control for said conveyor motor having a reference speed input and actual speed input and driving said motor such as to minimize the error therebetween;
- (b) a tachometer generator for generating a signal representative of the actual speed;
- (c) first means for supplying to said speed controller a first signal representative of a desired speed during the first pass; and
- (d) second means for supplying a second signal representing a desired speed during the second pass.
- 5. Apparatus according to claim 4 and further including means for establishing a minimum speed and means for establishing a maximum speed coupled to said first and second means for supplying.
- 6. Apparatus according to claim 5 wherein said speed controller comprises a regenerative speed control.
- 7. Apparatus according to claim 5 and further including means for manually supplying said desired speed signals to said motor controller and means associate therewith for automatically disconnecting inputs from said first and second means upon operation of said manual input.
- 8. Apparatus according to claim 5 and further including means for zeroing out the portion of said power which represents drive train and other losses and not power consumed in making pipe at no-load.
- 9. Apparatus according to claim 8 wherein said means for zeroing power comprises:
- (a) a computer programmed to: (i) sense the power output when said packer drive motor is rotating said packer without a load (ii) store said no-load power, and (iii) subtract said no-load power value from the sensed power at all times thereafter, said computer providing as an output the sensed power minus the power sensed with no load; and
- (b) means to couple the output of said computer as the actual value to said means to compare.
- 10. Apparatus according to claim 5 and further including: means to select a desired value of power; means to sense a value associated with said drive motor which at least approximately represents power; means to compare said sensed value with said desired value of power and provide as an output an error signal; and means to add said errors signal to said signal representative of desired speed supplied to said speed controller.
- 11. Apparatus according to claim 10 wherein said power is horsepower.
- 12. Apparatus according to claim 11 wherein said means to compare comprises an operational amplifier having a summing junction at its input, said amplifier having first and second variable resistors in its feedback path; and means to selectively switch said variable resistors into said feedback path, respectively during said first and second passes.
- 13. An electronic control system for an apparatus for forming concrete pipe of uniform density which includes: a mold having an inner wall, a packing head for packing concrete against the inner wall, a shaft centrally mounted on the packing head, a packing head motor for revolving the packing head through the mold; means for feeding concrete to the mold; a feed motor for driving the concrete feeding means; means for raising said packing head only at a fixed rate and lowering the packing head in at least one pass, comprising:
- (a) means for sensing and measuring the components of the actual power being used by the packing head motor said power being a function of torque generated in said packing head;
- (b) means for selecting a desired power;
- (c) means for zeroing out the portion of actual power which represents drive train and other losses at no load to obtain corrected power;
- (d) means for comparing said corrected power to said desired power; and
- (e) means for controlling the speed of said feed motor responsive to said means for comparing, such as to cause said actual power to be only constant and thereby said torque to also be constant, whereby said packing head will evenly pack concrete in said mold.
- 14. A control system for an apparatus for forming concrete pipe of uniform density which includes: a mold having an inner wall; a packing head for packing concrete against the innner wall; a shaft centrally mounted on the packing head; a packing head motor for revolving the packing head through the mold; means for feeding concrete to the mold; a feed motor for driving the concrete feeding means; and means for raising said packing head only at a fixed rate and lowering said packing head in at least one pass, comprising:
- (a) means for sensing and measuring the components of the actual power being used by the packing head motor said power being a function of torque generated in said packing head;
- (b) means for selecting a desired power;
- (c) an operational amplifier having a summing junction at its input, said amplifier having a variable resistor in its feedback path, for comparing said actual power to said desired power; and
- (d) means for controlling the speed of said feed motor responsive to the output of said operational amplifier, such as to cause said actual power to be only constant and thereby said torque to also be constant, whereby said packing head will evenly pack concrete in said mold.
- 15. Apparatus according to claim 14 wherein said operational amplifier has first and second variable resistors in its feedback path; and further including means to selectively switch said variable resistors into said feedback path, respectively during first and second passes of said packing head.
- 16. An apparatus for forming concrete pipe of uniform density comprising:
- (a) means for forming concrete into the form of said pipe comprising a mold having an inner wall, a packing head for packing concrete against said inner wall, a shaft centrally mounted on said packing head, a packing head motor for revolving said packing head through the mold and means for raising said packing head only at a fixed rate and lowering said packing head in at least one pass;
- (b) means for feeding concrete to said forming means;
- (c) a feed motor for driving said concrete feeding means;
- (d) means for sensing and measuring the components of the actual power being used by said packing head motor said power being a function of torque generated in said packing head;
- (e) means for selecting a desired power;
- (f) an operational amplifier having a summing junction at its input, said amplifier having a variable resistor in its feedback path for comparing said actual power to said desired power; and
- (g) means for controlling the speed of said feed motor responsive to the output of said operational amplifier.
- 17. Apparatus according to claim 16 wherein said operational amplifier has first and second variable resistors in its feedback path; and further including means to selectively switch said variable resistors into said feedback path, respectively during first and second passes.
- 18. An apparatus for forming concrete pipe of uniform density comprising:
- (a) means for forming concrete into the form of said pipe comprising a mold having an inner wall, a packing head for packing concrete against said inner wall, a shaft centrally mounted on said packing head, a packing head motor for revolving said packing head through the mold and means for raising said packing head only at a fixed rate and lowering said packing head in at least one pass;
- (b) means for feeding concrete to said forming means;
- (c) a feed motor for driving said concrete feeding means;
- (d) means for sensing and measuring the components of the actual power being used by said packing head motor said power being a function of torque generated in said packing head;
- (e) means for selecting a desired power;
- (f) means for zeroing out the portion of actual power which represents drive train and other losses at no load to obtain corrected power;
- (g) means for comparing said corrected power to said desired power; and
- (h) means for controlling the speed of said feed motor responsive to said means for comparing.
- 19. Apparatus according to claim 18 wherein said means for zeroing power comprises:
- (a) a computer programmed to: (i) sense the actual power output when said packer drive motor is rotating said packer without a load to obtain no-load power; (ii) store said no-load power, and (iii) subtract said no-load power from the sensed actual power at all times thereafter, to provide said corrected power, said computer providing as an output said corrected power; and
- (b) means to couple said corrected power output of said computer as the actual power input to said means for comparing.
- 20. Apparatus according to claim 18 wherein said means for zeroing power comprises:
- (a) a computer programmed to: (i) sense the actual power output when said packer drive motor is rotating said packing head with no-load to obtain no-load power; (ii) store said no-load power; and (iii) subtract said no-load power from the sensed actual power at all times thereafter, to provide said corrected power as an output; and
- (b) means to couple said corrected power output of said computer as the actual power input to said means for comparing.
- 21. An electronic control system for an apparatus for forming concrete pipe of uniform density which includes a mold having an inner wall, a packing head for packing concrete against the inner wall, a shaft centrally mounted on the packing head, a packing head motor for revolving the packing head through the mold; means for feeding concrete to the mold; a feed motor for driving the concrete feeding means; and means for raising said packing head only at a fixed rate and for lowering said packing head in at least one pass, comprising:
- (a) means for sensing and measuring the components of the actual power being used by the packing head motor said power being a function of torque generated in said packing head;
- (b) means for selecting a desired power;
- (c) means for comparing said sensed power to said desired power; and
- (d) means for controlling the speed of said feed motor responsive to said means for comparing, such as to cause said actual power to be only constant and thereby said torque to also be constant, whereby said packing head will evenly pack concrete in said mold.
- 22. Apparatus according to claim 21 wherein said means for sensing and measuring comprises means for sensing and measuring the components of horsepower.
- 23. Apparatus according to claim 21 wherein said speed controller comprises a regenerative speed control.
- 24. Apparatus according to claim 21 and further including means for zeroing out the portion of said actual power which represents drive train and other losses, at no-load, to obtain corrected power.
Parent Case Info
This application is a Continuation-In-Part of copending application Ser. No. 039,316, filed May 16, 1979 now U.S. Pat. No. 4,336,013.
US Referenced Citations (11)
Continuation in Parts (1)
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Number |
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Parent |
39316 |
May 1979 |
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