EXTRUSION APPARATUS HAVING ELECTRONIC INTERPOLATOR

• US 3,865,528 A
• Filed: 11/01/1973
• Issued: 02/11/1975
• Est. Priority Date: 11/01/1973
• Status: Expired due to Term

• Current Assignee: Louis G. Roess
• Original Assignee: Louis G. Roess
• Inventors: Roess, Louis G.
• Primary Examiner(s): Annear, R. Spencer
• Assistant Examiner(s): Rosenbaum, Mark
• Application Number:
  US05/411,830
• Time in Patent Office: 467 Days
• Field of Search: 264/40 235/151.11 425/376,162,166,167,141,381,145,147,140,150,380,465,466,461,308
• US Class Current: 425/145
• CPC Class Codes: B29C 2948/9218 Weight
• CPC Class Codes: B29C 2948/92571 Position, e.g. linear or angular
• CPC Class Codes: B29C 2948/92638 Length
• CPC Class Codes: B29C 2948/92647 Thickness
• CPC Class Codes: B29C 48/09 Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
• CPC Class Codes: B29C 48/325 being adjustable , i.e. having adjustable exit sections
• CPC Class Codes: B29C 48/388 using a screw extruder and a ram or piston
• CPC Class Codes: B29C 48/92 Measuring, controlling or regulating
• CPC Class Codes: G05B 19/08 using plugboards, cross-bar distributors, matrix switches, or the like

Abstract

The improvement in cyclically operated extrusion apparatus of providing electronic interpolator means responsive to different portions of the total range of a continuously variable signal which is provided during each cycle of operation, programmable means for selecting portions of the interpolator output signals, means for summing such programmed output signals to provide a command signal for servocontroller means which effects relative movement between a die head and pintle to provide a variable orifice through which extrudable material is forced to form a parison of controlled wall thickness. Variations of the broad concept contemplate generating the continuously variable signal by an electrical transducer machine slaved to some movable element of the apparatus, or by a ramp generator which may have an electromechanical integrator or an electronic integrator. More specific features include the capability of selecting two or more programs, serviced by a single electronic interpolator means, for simultaneous control of a corresponding number of separate functions.

Claims

1. In cyclically operated extrusion apparatus including a die head and pintle movable relative to each other to provide a variable orifice, servocontroller means responsive to an electrical command signal for effecting relative movement between said die head and pintle and means for forcing extrudable material through said orifice to form a parison the wall thickness of which is detErmined by the size of said orifice, wherein the improvement comprises means providing said command signal including means providing a continuously variable electrical signal related to the parison forming sequence of each cycle of operation, electronic interpolator means to provide a plurality of interpolator output electrical signals responsive to different portions of the total range of said variable signal, programmable means for selecting portions of said interpolator output signals to provide programmed output signals and means for summing said programmed output signals to provide said command signal.

2. Extrusion apparatus according to claim 1 wherein said electronic interpolator means comprises a plurality of electronic amplifier means having distributed biases to provide said interpolator output electrical signals.

3. Extrusion apparatus according to claim 2 wherein said biases are linearly distributed.

4. Extrusion apparatus according to claim 2 wherein said biases are nonlinearly distributed.

5. Extrusion apparatus according to claim 1 wherein said programmable means comprises a plurality of impedance strings severally receiving said interpolator output signals, each of said strings permitting one of said programmed output signals to be selectively determined.

6. Extrusion apparatus according to claim 1 further comprising an element which moves when said parison is forming, and said means for providing a continuously variable electrical signal is an electircal transducer responsive to movement of said element.

7. Extrusion apparatus according to claim 6 wherein said movable element is an acumulator piston.

8. Extrusion apparatus according to claim 6 wherein said movable element is a parison neck ring.

9. Extrusion apparatus according to claim 1 wherein said means for providing a continuously variable electrical signal is a ramp generator.

10. Extrusion apparatus according to claim 9 wherein said ramp generator includes an electronic integrator.

11. Extrusion apparatus according to claim 9 wherein said ramp generator includes an electromechanical integrator.

12. Extrusion apparatus according to claim 6 wherein said transducer comprises a potentiometer.

13. Extrusion apparatus according to claim 1 wherein said servocontroller means comprises an electrohydraulic servovalve and actuator.

14. Extrusion apparatus according to claim 2 further comprising settable gain means responsive to said continuously variable signal for adjusting the quantity of material extruded in a cycle of operation.

15. Extrusion apparatus according to claim 1 further comprising settable bias means operatively associated with said continuously variable signal for adjusting the occurrence of extrusion during a cycle of operation.

16. Extrusion apparatus according to claim 1 wherein said programmable means includes a plurality of impedance strings severally receiving said interpolator output signals, first shorting bar means, selectively movable first pins operatively associated with said impedance strings and said first shorting bar means for providing first programmed output signals, second shorting bar means and selectively movable second pins operatively associated with said impedance strings and said second shorting bar means for providing second programmed output signals, said summing means sums said first programmed output signals to provide said command signal for said servocontroller means, and further comprising second servocontroller means responsive to a second command signal for effecting relative movement between two parts utilized in the formation of a parison, and second means for summing said second programmed output signals to provide said second command signal.

17. Extrusion apparatus according to claim 16 wherein said two parts comprise another die head and pintle separate from the first mentioned die head and pintle.

18. Extrusion apparatus according to claim 16 wherein one of said parts is said die head and the other of said Parts is a die thereon and movable relative thereto in a direction transverse to the direction of said relative movemant between said die head and pintle.

19. Extrusion apparatus according to claim 18 wherein said die is movable relative to said die head in another direction transverse to the direction of said relative movement between said die head and pintle, said programmable means includes third shorting bar means and selectively movable third pins operatively associated with said impedance strings and said third shorting bar means for providing third programmed output signals, and further comprising third servocontroller means responsive to a third command signal for effecting relative movement between said die and die head in said another direction, and third means for summing said third programmed output signals to provide said third command signal.