Apparatus and method for inspecting glass containers

In an inspection apparatus including an inspection station for rotating a transparent container about its longitudinal axis, a light source for illuminating the interior of the container, a detector assembly mounted adjacent the side wall of the container and having light responsive means spaced apart along a line substantially parallel to the longitudinal axis of the container for generating at least one upper input signal and at least one lower input signal, each input signal with a characteristic proportional to the amount of light transmitted through the side wall from the light source and a detection circuit for monitoring the input signals and for generating an output signal in response to a predetermined change in the light proportional characteristic of the input signals, the output signal representing the detection of a predetermined type of defect, the detection circuit comprising:

• amplifier means responsive to the upper and lower input signals for generating amplified signals having a first signal component representing the average light proportional characteristic of the corresponding one of the upper and lower input signals generated by the transmission of the light through an unobstructed side wall of the container and a second signal component representing the percentage deviation from the average light proportional characteristic of the corresponding one of the upper and lower input signals generated by the transmission of light through an obstruction in the side wall of the container;
• filter means responsive to said amplified signals for separating each of said first signal components from said associated second signal component;
• comparison means for generating reference signals, for comparing the light proportional characteristic of each of said separated second signal components with the magnitudes of at least two of said reference signals and for generating a detection signal for each of said separated second signal components having a light proportional characteristic which exceeds the magnitude of the one of said reference signals being compared, each of said reference signals having a different magnitude representing a percentage deviation from the average light proportional characteristic of the one of said input signals being compared;
• logic circuit means including timing means responsive to said detection signals for generating a signal having a duration representing a predetermined amount of rotation of the container after a first one of said detection signals is received, said logic circuit means being responsive to said detection signals and said timing means signal for generating the output signal in response to the receipt of at least one of said detection signals during the duration of said timing means signal.

In an inspection apparatus including an inspection station for rotating a glass container about its longitudinal axis, a light source for illuminating the interior of the container, a detector assembly mounted adjacent the side wall of the container and having an upper pair and a lower pair of light responsive means spaced apart along a line substantially parallel to the longitudinal axis of the container, each of the light responsive means generating an input signal with a characteristic proportional to the amount of light transmitted through the side wall from the light source, and a detection circuit for monitoring the input signals and for generating an output signal in response to a predetermined change in the light proportional characteristic of the input signals, the output signal representing the detection of a predetermined type of defect, the detection circuit comprising:

• amplifier means responsive to the input signals for generating amplified signals having the light proportional characteristic of the associated input signals;
• comparison means for generating reference signals, for comparing the light proportional characteristic of said amplified signals with the magnitude at least one of said reference signals and for generating detection signals when a predetermined relationship exists between the light proportional characteristic of said amplified signals and the magnitude said reference signal;
• and
• logic circuit means responsive to said detection signals for generating a timing signal having a duration representing a predetermined amount of rotation of the container and for generating the output signal in response to the generation of at least one of said detection signals during the duration of said timing signal.

In an inspection apparatus including an inspection station for rotating a glass container about its longitudinal axis, a light source for illuminating the interior of the container, a detector assembly mounted adjacent the side wall of the container and having an upper pair and a lower pair of light responsive means spaced apart along a line substantally parallel to the longitudinal axis of the container, each of the light responsive means generating an input signal having a magnitude proportional to the amount of light transmitted through the side wall from the light source, and a detection circuit for monitoring the input signals and for generating an output signal in response to a predetermined change in the magnitude of one or more of the input signals, the output signal representing the detection of a predetermined type of defect, the detection circuit comprising:

• means responsive to the input signals for generating signal components having magntidues representing the percentage deviation from the average magnitudes of each of the input signals, said deviations generated by the transmission of light through an obstruction in the side wall;
• means for generating first through fourth reference signals having magnitudes representing large, average and small reduction and small increase percentage deviations respectively;
• means for comparing said signal components with each of said reference signals and for generating first through fourth detection signals when the magnitudes of each of said signal components exceeds the magnitudes of said first through fourth reference signals respectively;
• means for generating a first timing signal initiated by the generation of a first one of any of said first through fourth detection signals, terminated at the termination of a first time delay and having a duration representing a first predetermined amount of rotation, a second timing signal initiated at the termination of said first time delay, terminated at the termination of a second time delay and having a duration representing a second predetermined amount of rotation and a third timing signal initiated at the termination of said second time delay, terminated at the termination of a third time delay and having a duration representing a third predetermined amount of rotation;
• and
• means responsive to said timing signals and said detection signals for generating said output signal in response to difference of a predetermined amount between the lengths of time of generation of said second detection signals for the upper and lower pairs of light responsive means during the duration of said first timing signal, in response to the generation of at least said second detection signals corresponding to one of said pairs of light responsive means, the generation of at least one of said first detection signals and no more than two of either of said third and fourth detection signals during the duration of said first timing signal, in response to the generation of at least two of said second detection signals during the duration of said second timing signal, or in response to the generation of at least two of said second detection signals during the duration of said third timing signal.

A method for inspecting the side walls of a glass container wherein the container is rotated about its longitudinal axis and a light source illuminates the interior of the container comprising the steps of:

• generating first signals having a magnitude representing the amount of light transmitted through the side wall of the container for at least two spaced apart positions along a line substantially parallel to the longitudinal axis of the container;
• generating a second signal having a magnitude representing the percentage deviation from the average magnitude of each of said first signals in response to the transmission of the light through an obstruction in the side wall;
• comparing the magnitudes of said second signals with the magnitude of a reference signal;
• generating a detection signal when the magnitude of each of said second signals exceeds the magnitude of said reference signal;
• generating a timing signal having a duration representing a predetermined amount of rotation of the container after a first one of said detection signals is generated;
• and
• generating an output signal representing the detection of a predetermined type of defect in response to the receipt of at least one of said detection signals during the duration of said timing signal.