Size control device for continuously produced elongate object

Claim 2

A size control device for an extrusion molding machine in which an extruded material is drawn by draw-off means, comprising an opto-electric scanning means for optically scanning the extruded material and producing an electrical signal representative of a cross-sectional size of the scanned extruded material, a first comparator circuit for comparing the signal from the scanning means with a first reference signal representative of a predetermined cross-sectional size of the extruded material for producing an output signal representative of an amount of deviation of the detected cross-sectional size of the scanned extruded material from the predetermined crosssectional size, a second comparator circuit for comparing the output signal of the first comparator circuit with a reference signal representative of a prescribed allowable range of deviation of the detected cross-sectional size of the extruded material from the predetermined croSs-sectional size for passing therethrough the output signal of the first comparator circuit when the detected cross-sectional size of the scanned extruded material falls outside the prescribed allowable range, a control signal generating circuit responsive to the output signal passed from the second comparator circuit for providing a control signal having a duration which is representative of the amount of deviation of the detected cross-sectional size of the scanned extruded material, drive means triggered by said control signal for driving said draw-off means to change the rate of drawing the extruded material for an interval which corresponds to the duration of the control signal, and a timing circuit connected to an output terminal of said control signal generating circuit for producing an output signal having a predetermined duration in response to the control signal delivered from the control signal generating circuit, and a holding circuit having an input terminal connected to an output terminal of the timing circuit and an output terminal connected to said second comparator circuit for holding the second comparator circuit in a locked condition for a time interval which is equal to the duration of the output signal from the timing circuit so that the delivery of the output signal from the second comparator circuit to said control signal generating circuit is interrupted for said time interval.

Claim 3

A size control device for controlling the cross-sectional size of a non-transparent elongate object which is continuously produced and conveyed in a predetermined path, comprising, in combination, opto-electric scanning means consisting essentially of a light-emitting unit having a predetermined optical axis and operative to emit a collimated beam of light on the optical axis and a light-sensitive unit which has an optical axis substantially in line with the optical axis of the light-emitting unit and which is spaced apart from the light-emitting unit in a direction parallel with the aligned optical axes of the units, the light-sensitive unit comprising a dark chamber formed with a pinhole aligned with the optical axis of the light-sensitive unit and a light-sensitive semiconductor element located behind said pinhole and in alignment with the optical axis of the light-sensitive unit for producing an electric current when irradiated with the beam of light from said light-emitting unit through said pinhole, the light-emitting and light-sensitive units being movable together in direction substantially perpendicular to the optical axes thereof with said path of the object extending intermediate the two units and substantially perpendicularly to the optical axes of the units so that the collimated beam of light emitted from the light-emitting unit toward the light-sensitive unit is intercepted by and in the presence of the object on the optical axes of the units and an electric signal representative of the cross-sectional size of the object which has intercepted the beam of light is produced from the light-sensitive unit, a first comparator circuit for comparing the electric signal from said light-sensitive unit with a first reference signal representative of a predetermined cross-sectional size of the object for producing an output signal representative of an amount of deviation of the detected cross-sectional size of the object from the predetermined cross-sectional size, a second comparator circuit for comparing the output signal from the first comparator circuit with a second reference signal representative of a prescribed allowable range of deviation of the detected cross-sectional size of the scanned object from the predetermined cross-sectional size of the object for passing therethrough the output signal of the first comparator circuit when the detected cross-sectional size of the object falls outside the prescribed range, a control signal generating circuit responsive to the signal passed through the second comparator circuit for producing a control signal having a dUration which is representative of the amount of deviation of the detected cross-sectional size of the scanned object from the predetermined cross-sectional size, and drive means operative to be triggered by said control signal for changing the rate of conveying the object in said path for a duration corresponding to the duration of the control signal.

Claim 4

A size control device for controlling the cross-sectional size of a non-transparent elongate object which is continuously produced and conveyed in a predetermined path, comprising, in combination, opto-electric scanning means consisting essentially of a light-emitting unit having a predetermined optical axis and operative to emit a collimated beam of light on the optical axis and a light-sensitive unit which has an optical axis substantially in line with the optical axis of the light-emitting unit and which is spaced apart from the light-emitting unit in a direction parallel with the aligned optical axes of the units, the light-sensitive unit comprising a dark chamber formed with a pinhole aligned with the optical axis of the light-sensitive unit and a light-sensitive semiconductor element located behind said pinhole and in alignment with the optical axis of the light-sensitive unit for producing an electric current when irradiated with the beam of light from said light-emitting unit through said pinhole, the light-emitting and light-sensitive units being movable together in direction substantially perpendicular to the optical axes thereof with said path of the object extending intermediate the two units and substantially perpendicularly to the optical axes of the units so that the collimated beam of light emitted from the light-emitting unit toward the light-sensitive unit is intercepted by and in the presence of the object on the optical axes of the units and an electric signal representative of the cross-sectional size of the object which has intercepted the beam of light is produced from the light-sensitive unit, a first comparator circuit for comparing the electric signal from said light-sensitive unit with a first reference signal representative of a predetermined cross-sectional size of the object for producing an output signal representative of an amount of deviation of the detected cross-sectional size of the object from the predetermined cross-sectional size, a second comparator circuit for comparing the output signal from the first comparator circuit with a second reference signal representative of a prescribed allowable range of deviation of the detected cross-sectional size of the scanned object from the predetermined cross-sectional size of the object for passing therethrough the output signal of the first comparator circuit when the detected cross-sectional size of the object falls outside the prescribed range, a control signal generating circuit responsive to the signal passed through the second comparator circuit for producing a control signal having a dUration which is representative of the amount of deviation of the detected cross-sectional size of the scanned object from the predetermined cross-sectional size, and drive means operative to be triggered by said control signal for changing the rate of conveying the object in said path for a duration corresponding to the duration of the control signal.

Claim 5

A size control device as set forth in claim 2, in which said light-sensitive unit further comprises an apertured member having an aperture located on the optical axis of the light-sensitive unit and intermediate said pinhole and said light-sensitive semiconductor element.

Claim 6

A size control device as set forth in claim 2, in which said light-emitting unit comprises a light-emissive semiconductor element which is located on the optical axis of the light-emitting unit.

Claim 7

A size control device as set forth in claim 4, in which said light-emitting unit further comprises a condensing lens which is located intermediate said light-emissive semiconductor element and said light-sensitive unit.

Claim 8

A size control device as set forth in claim 2, in which said light-emitting and light-sensitive units are movable toward and away from each other in a direction parallel with the optical axes of the units.

Claim 9

A size control device as set forth in claim 2, further comprising a timing circuit connected to an output terminal of said control signal generating circuit for producing an output signal having a predetermined duration in response to the control signal delivered from said control signal generating circuit, and a holding circuit having an input terminal connected to an output terminal of said timing circuit and an output terminal connected to said second comparator circuit, said holding circuit being operative to hold the second comparator circuit in a locked condition responsive to the output signal from said timing circuit, said locked condition being maintained for a period of time equal to the duration of the output signal from the second comparator circuit whereby the delivery of the output signal from the second comparator circuit to said control signal generator is interrupted for said period of time.