Control system for parison extruders

Claim 2

A control system for an extruder of the type effective to extrude a parison, said extruder including a die with an opening therein, a mandrel disposed within said opening, the mandrel and die being shiftable relative to one another to cause a change in the thickness of the extruded parison during the parison extrusion cycle, drive means for effecting relative movement between said die and mandrel, an electronic programmer, a servo amplifier for energizing said drive means in accordance with signals received from said electronic programmer, a transducer for providing an electric signal to said servo amplifier correlated with the relative position of said die and mandrel, said electronic programmer including a set of conductors, each of the conductors of said set having a unique electrical characteristic associated therewith, means for selectively establishing the electrical characteristic associated with each of said conductors, an electronic clock effective to produce periodic output signals at predetermined time intervals, means for initiating operation of said clock in correlation with initiation of the parison extrusion cycle, electronic switching means actuated by the output signals from said clock, said electronic switching means being effective to sequentially sample the electrical characteristics of each of the conductors of said set and to apply signals to said servo amplifier correlated therewith, said electronic switching means being effective to sample the electrical characteristics of the first of said conductors at the start of the parison extrusion cycle and being effective to sample the last of the conductors at the end of the parison extrusion cycle.

Claim 3

A control system for an extruder of the type effective to extrude a parison, said extruder including a die with an opening therein, a mandrel disposed within said opening, the mandrel and die being shiftable relative to one another to cause a change in the thickness of the extruded parison during the parison extrusion cycle, drive means for effecting relative movement between said die and mandrel, an electronic programmer, a servo amplifier for energizing said drive means in accordance with signals received from said electronic programmer, a transducer for providing an electric signal to said servo amplifier correlated with the relative position of said die and mandrel, said electronic programmer including a set of conductors, each of the conductors of said set having a unique characteristic potential thereon, means for selectively establishing the potential on each of said set of conductors, an electronic clock effective to produce periodic output signals at predetermined time intervals, means for initiating operation of said clock in correlation with initiation of the parison extrusion cycle, electronic switching means actuated by the output signals from said clock, said electronic switching means being effective to sequentially sample the voltages of each of the conductors of said set and to apply signals to said servo amplifier correlated therewith, said electronic switching means being effective to sample the electrical characteristics of the first of said conductors at the start of the parison extrusion cycle and being effective to sample the last of the conductors at the end of the parison extrusion cycle.

Claim 4

A control system for an extruder of the type effective to extrude a parison, said extruder including a die with an opening therein, a mandrel disposed within said opening, the mandrel and die being shiftable relative to one another to cause a change in the thickness of the extruded parison during the parison extrusion cycle, drive means for effecting relative movement between said die and mandrel, an electronic programmer, a servo amplifier for energizing said drive means in accordance with signals received from said electronic programmer, a transducer for providing an electric signal to said servo amplifier correlated with the relative position of said die and mandrel, said electronic programmer including a set of conductors, each of the conductors of said set having a unique characteristic potential thereon, means for selectively establishing the potential on each of said set of conductors, an electronic clock effective to produce periodic output signals at predetermined time intervals, means for initiating operation of said clock in correlation with initiation of the parison extrusion cycle, electronic switching means actuated by the output signals from said clock, said electronic switching means being effective to sequentially sample the voltages of each of the conductors of said set and to apply signals to said servo amplifier correlated therewith, said electronic switching means being effective to sample the electrical characteristics of the first of said conductors at the start of the parison extrusion cycle and being effective to sample the last of the conductors at the end of the parison extrusion cycle.

Claim 5

A control system according to claim 2 wherein said electronic switching means comprises, a shift register triggered by said clock, said shift register comprising a set of bit positions each corresponding to a respective one of said conductors of said second set, a set of electronic switching elements each connected between a different one of said set of conductors and said servo amplifier and eaCh responsive to the presence of a bit in the corresponding bit position of said shift register to connect said conductor and to apply a signal correlated therewith to said servo amplifier.

Claim 6

A control system according to claim 3 further comprising, means connecting said shift register in circular form, means to set a bit in the bit position of said shift register associated with the first conductor of the set, means to cause said bit to advance progressively through said bit positions of said shift register to sequentially apply the voltage on said conductors to said servo amplifier.

Claim 7

A control system according to claim 2 wherein said switching means comprises, a set of high impedance switching circuits each including a different one of said conductors and said servo amplifier.

Claim 8

A control system according to claim 5 wherein each of said high impedance switching circuits include a field effect transistor.

Claim 9

A control system according to claim 2 further comprising, a voltage divider having a set of intermediate points each connected to one of the conductors of a second set to impress said unique characteristic potential thereon, and means for selectively interconnecting each of said second set of conductors with one of said first set of conductors.

Claim 10

A control system according to claim 7 wherein said set of intermediate points impresses equally spaced characteristic potentials on said second set of conductors.

Claim 11

A control system according to claim 7 wherein said switching means comprises, a set of high impedance switching circuits each connected to a different one of said conductors wherein the voltages on said voltage divider are not materially altered by the switching of switching circuits.

Claim 12

A control system according to claim 2 further comprising, settable control means for modifying the signal of said electronic programmer, said servo amplifier energizing said drive means in accordance with the signal from said electronic programmer as modified by said control means.

Claim 13

A control system according to claim 10 for a plurality of extruders, further comprising, a second drive means for effecting relative movement between a second die and mandrel, a second servo amplifier energizing said second drive means in accordance with the signal received from said electronic programmer, a second transducer for providing an electronic feedback signal to said second servo amplifier correlated with the position of said second die and mandrel, and said control means being settable to provide means to control plural extruders to produce identical articles despite variations in said extruders.

Claim 14

A control system according to claim 2 further comprising, settable control means, said servo amplifier for energizing said drive means in accordance with the algebraic sum of signals received from said electronic programmer and said settable control means.

Claim 15

A control system according to claim 2 wherein, said electronic clock emits said periodic output signals at equal time intervals, the operating cycle of said extruder is an integral multiple of the said equal time intervals between periodic signals of said electronic clock, and means for varying the length of said time intervals.

Claim 16

A control system for an extruder of the type effective to extrude a parison, said extruder including a die with an opening therein, a mandrel disposed within said opening, the mandrel and die being shiftable relative to one another to cause a change in the wall thickness of the extruded parison, and drive means for effecting relative movement between said die and mandrel, an electronic programmer; a servo amplifier for energizing said drive means in accordance with signals received from said electronic programmer; a transducer for providing an electric feedback signal to said servo amplifier correlated with the relative position of said die and mandrel; a circuit for applying signals to said servo amplifier in accordance with the impedance in said circuit; said electronic programmer including a matrix consisting of first and second sets of conductors; each of the conductors of said first set having a unique characterizing impedance associated therewith; means for selectively interconnecting each of said second set of conductors with one of said first set of conductors; an electronic clock effective to produce periodic output signals at predetermined time intervals; means for initiating operation of said clock in correlation with initiation of the parison extrusion cycle; electronic switching means actuated by the output signals from said clock; said electronic switching means being effective to sequentially select each of the leads of said second set to connect the impedance associated therewith to said circuit; said electronic switching means being effective to select the first of said leads at the start of the extrusion cycle and being effective to select the last of the leads at the end of the extrusion cycle.

Claim 17

A control system for an extruder of the type effective to extrude a parison, said extruder including a die with an opening therein, a mandrel disposed within said opening, the mandrel and die being shiftable relative to one another to cause a change in the wall thickness of the extruded parison, and drive means for effecting relative movement between said die and mandrel, an electronic programmer; a servo amplifier for energizing said drive means in accordance with signals received from said electronic programmer; a transducer for providing an electric feedback signal to said servo amplifier correlated with the relative position of said die and mandrel; a circuit for applying signals to said servo amplifier in accordance with the impedance in said circuit; said electronic programmer including a matrix consisting of first and second sets of conductors; each of the conductors of said first set having a unique characterizing impedance associated therewith; means for selectively interconnecting each of said second set of conductors with one of said first set of conductors; an electronic clock effective to produce periodic output signals at predetermined time intervals; means for initiating operation of said clock in correlation with initiation of the parison extrusion cycle; electronic switching means actuated by the output signals from said clock; said electronic switching means being effective to sequentially select each of the leads of said second set to connect the impedance associated therewith to said circuit; said electronic switching means being effective to select the first of said leads at the start of the extrusion cycle and being effective to select the last of the leads at the end of the extrusion cycle.

Claim 18

A control system according to claim 14 wherein said electronic switching means comprises, a shift register triggered by said clock output signals, said shift register comprising a set of bit positions each corresponding to a respective one of said conductors of said second set, a set of electronic switching elements each connected in series with a different one of said leads of said second set of conductors and each responsive to the presence of a bit in the corresponding bit position of said shift register to select said leads.

Claim 19

A control system according to claim 15 further comprising, means connecting said shift register in circular form, means for setting a bit in the bit position of said shift register associated with the first conductor of said second set, means to cause said bit to advance progressively through said bit positions of said shift register.

Claim 20

A control system according to claim 14 wherein said circuit comprises, a constant current source, and said characterizing impedances being selectively connectable by the actuation of said switching means in series with said source.

Claim 21

A control system according to claim 17 wherein said circuit further comprises an amplifier connected across said impedances and in series with said source for applying said signals to said servo in accordance with the voltage across said impedances.

Claim 22

A control system according to claim 14 further comprising: a set of resistors connected in series, resistors of said set being connected between pairs of conductors of said first set to associate said unique characterizing impedances therewith.

Claim 23

A control system according to claim 19 wherein said characterizing impedances on said first set of conductors are a series of impedances equally spaced in value.

Claim 24

A control system according to claim 19 wherein said switching means comprises, a set of solid state switches each connected between a different one of said conductors of said second set and said circuit to selectively connect said impedances into said circuit.

Claim 25

A control system according to claim 17 further comprising: settable control means for modifying the current of said source, to alter the relation of the signal from said circuit to the impedances of said circuit.

Claim 26

A control system according to claim 22 for a plurality of extruders, further comprising a second drive means for effecting relative movement between a second die and mandrel, a second servo amplifier energizing said second drive means in accordance with the signal received from said electronic programmer, a second transducer for providing an electronic feed-back signal to said second servo amplifier correlated with the position of said second die and mandrel, and said control means being settable to provide means to control plural extruders To produce identical articles despite variations in said extruders.

Claim 27

A control system according to claim 14 further comprising, settable control means, said servo amplifier being operative to energize said drive means in accordance with the algebraic sum of signals received from said electronic programmer and said settable control means.

Claim 28

A control system according to claim 14 wherein, said electronic clock emits said periodic output signals at equal time intervals, the operating cycle of said extruder is an integral multiple of the equal time intervals between periodic signals of said electronic clock, and means for varying the length of said time intervals.

Claim 29

The control system of claim 14 further comprising means for controlling auxiliary machine functions in timed relationship to the cycle of operation of said extruder, said means for controlling auxiliary machine functions comprising, electrically responsive actuator means for controlling said auxiliary machine functions, an auxiliary patch panel including a matrix consisting of first and second sets of conductors, each of the conductors of said first set being interconnected to one of said actuators, means for selectively interconnecting each of said second set of conductors with one of said first set of conductors, said electronic switching means being effective to sequentially apply a voltage to each of the leads of said second set of said auxiliary patch panel.

Claim 30

The control system of claim 14 further including means for producing an asymmetric change of thickness of said tube, said last named means comprising, second drive means for effecting relative transverse movement between said die and said mandrel, a second electronic programmer, a second servo amplifier for energizing said drive means in accordance with signals received from said electronic programmer, a second transducer for providing an electric feed-back signal to said servo amplifier correlated with the relative position of said mandrel and die member.

Claim 31

A control system for an extruder of the type effective to extrude a parison, said extruder including a die with an opening therein, a mandrel disposed within said opening, the mandrel and die being shiftable relative to one another transversely of the axis of said mandrel to cause an asymmetric change in the thickness of the extruded parison, wherein one portion of the parison wall is thicker than the opposite portion; drive means for effecting relative transverse movement between said die and mandrel; an electronic programmer; a servo amplifier for energizing said drive means in accordance with signals received from said electronic programmer; a transducer for providing an electric feedback signal to said servo amplifier correlated with the relative position of said mandrel and die member; said electronic programmer including a matrix consisting of first and second sets of conductors; each of the conductors of said first set having a unique electrical characteristic associated therewith; means for selectively interconnecting each of said second set of conductors with one of said first set of conductors; an electronic clock effective to produce periodic output signals at predetermined equal time intervals; means for initiating operation of said clock in correlation with initiation of the parison extrusion cycle; electronic switching means actuated by the output signals from said clock; said electronic switching means being effective to sequentially sample the electrical characteristics of each of the leads of said second set and to apply signals to said servo amplifier correlated therewith; said electronic switching means being effective to sample the electrical characteristics of the first of said leads at the start of the parison extrusion cycle and being effective to sample the last of the leads at the end of the parison extrusion cycle.

Claim 32

A control system for an extruder of the type effective to extrude a parison, said extruder including a die with an opening therein, a mandrel disposed within said opening, the mandrel and die being shiftable relative to one another transversely of the axis of said mandrel to cause an asymmetric change in the thickness of the extruded parison, wherein one portion of the parison wall is thicker than the opposite portion; drive means for effecting relative transverse movement between said die and mandrel; an electronic programmer; a servo amplifier for energizing said drive means in accordance with signals received from said electronic programmer; a transducer for providing an electric feedback signal to said servo amplifier correlated with the relative position of said mandrel and die member; said electronic programmer including a matrix consisting of first and second sets of conductors; each of the conductors of said first set having a unique electrical characteristic associated therewith; means for selectively interconnecting each of said second set of conductors with one of said first set of conductors; an electronic clock effective to produce periodic output signals at predetermined equal time intervals; means for initiating operation of said clock in correlation with initiation of the parison extrusion cycle; electronic switching means actuated by the output signals from said clock; said electronic switching means being effective to sequentially sample the electrical characteristics of each of the leads of said second set and to apply signals to said servo amplifier correlated therewith; said electronic switching means being effective to sample the electrical characteristics of the first of said leads at the start of the parison extrusion cycle and being effective to sample the last of the leads at the end of the parison extrusion cycle.

Claim 33

The control system of claim 28 in which said die is shiftable from a position in which the opening is concentric with said mandrel to a position in which the opening is eccentric with respect to the mandrel and said drive means is interconnected to said die.

Claim 34

A control system for an extruder of the type effective to extrude a parison, said extruder including a die with an opening therein, a mandrel disposed within said opening, the mandrel and die being shiftable relative to one another to cause a change in the thickness of the extruded parison during the parison extrusion cycle, drive means for effecting relative movement between said die and mandrel, an electronic programmer operable through a control cycle, a servo amplifier for energizing said drive means in accordance with signals received from said electronic programmer, a transducer for providing an electric signal to said servo amplifier correlated with the relative position of said die and mandrel, said electronic programmer including a set of conductors, each of the conductors of said set having a unique electrical characteristic associated therewith, means for selectively establishing the electrical characteristic associated with each of said conductors, a control for effecting the total length of said control cycle, whereby said length can be matched to the length of the parison extrusion cycle, an electronic pulse generator effective to produce signals at predetermined intervals throughout said control cycle, means for automatically electrically dividing said control cycle into said predetermined number of intervals, means for initiating operation of said pulse generator to initiate said control cycle in correlation with initiation of the parison extrusion cycle, electronic switching means actuated by the output signals from said pulse generator, said electronic switching means being effective to sequentially sample the electrical characteristics of each of the conductors of said set and to apply signals to said servo amplifier correlated therewith, said electronic switching means being effective to sample the electrical characteristics of the first of said conductors at the start of the parison extrusion cycle and being effective to sample the last of the conductors at the end of the parison extrusion cycle.

Claim 35

A control system for an extruder of the type effective to extrude a parison, said extruder including a die with an opening therein, a mandrel disposed within said opening, the mandrel and die being shiftable relative to one another to cause a change in the thickness of the extruded parison during the parison extrusion cycle, drive means for effecting relative movement between said die and mandrel, an electronic programmer operable through a control cycle, a servo amplifier for energizing said drive means in accordance with signals received from said electronic programmer, a transducer for providing an electric signal to said servo amplifier correlated with the relative position of said die and mandrel, said electronic programmer including a set of conductors, each of the conductors of said set having a unique electrical characteristic associated therewith, means for selectively establishing the electrical characteristic associated with each of said conductors, a control for effecting the total length of said control cycle, whereby said length can be matched to the length of the parison extrusion cycle, an electronic pulse generator effective to produce signals at predetermined intervals throughout said control cycle, means for automatically electrically dividing said control cycle into said predetermined number of intervals, means for initiating operation of said pulse generator to initiate said control cycle in correlation with initiation of the parison extrusion cycle, electronic switching means actuated by the output signals from said pulse generator, said electronic switching means being effective to sequentially sample the electrical characteristics of each of the conductors of said set and to apply signals to said servo amplifier correlated therewith, said electronic switching means being effective to sample the electrical characteristics of the first of said conductors at the start of the parison extrusion cycle and being effective to sample the last of the conductors at the end of the parison extrusion cycle.

Claim 36

The control system of claim 30 in which said die is shiftable from a position in which the opening is concentric with said mandrel to a position in which the opening is eccentric with respect to the mandrel and said drive means is interconnected to said die.

Claim 37

The control system of claim 2 further including means for producing an asymmetric change of thickness of said tube, said last named means comprising, second drive means for effecting relative transverse movement between said die and said mandrel, a second electronic programmer, a second servo amplifier for energizing said drive means in accordance with signals received from said electronic programmer, a second transducer for providing an electric feed-back signal to said servo amplifier correlated with the relative position of said mandrel and die member.

Claim 38

The control system of claim 2 further comprising means for controlling auxiliary machine functions in timed relationship to the cycle of operation of said extruder, said means for controlling auxiliary machine functions comprising, electrically responsive actuator means for controlling said auxiliary machine functions, an auxiliary patch panel including a matrix consisting of first and second sets of conductors, each of the conductors of said first set being interconnected to one of said actuators, means for selectively interconnecting each of said second set of conductors with one of said first set of conductors, said electronic switching means being effective to sequentially apply a voltage to each of the leads of said second set of said auxiliary patch panel.