US3780859A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method for displaying the minimum thickness of a dielectric member measured by a radio frequency thickness gauge
Assignee: OI Glass Inc
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Filing: 1973-02-08
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Granted: 1973-12-25
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Expires: 1993-02-08
Abstract
Abstract Apparatus and method for displaying the minimum thickness of a glass container which is measured for thickness by a radio frequency thickness gauge. One type of thickness measuring device for glass containers uses the attenuation of a radio frequency signal as a linear measure of thickness in terms of voltages. The output voltage is scaled to obtain a voltage which is numerically equal to the value of thickness of the container in thousandths of an inch. The thickness of the container may vary over a range of thicknesses. This invention will hold the minimum thickness measured for a particular container and display this, in terms of the scaled voltage, as a digital number. This aids in detecting and diagnosing thickness flaws in glass containers. The circuit for holding the minimum thickness is erased of its previous reading and reset to accept a new minimum thickness as the measurement of a new container is begun.
Inventors
- 👤 G Scherf
- 👤 R Kohler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:43
CPC Classifications
G; G01; G01B; G01B15/00; G01B15/02; G01B7/00; G01B7/02; G01B7/06
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
476 words
In an apparatus for measuring the thickness of an article formed from a dielectric material wherein an antenna is used to establish a radio frequency field outwardly in the direction of an article positioned adjacent thereto; a probe is positioned in said field adjacent to said article; the voltage induced in said probe is an index of the thickness of that portion of said article immediately in front of said probe; a compensated reference voltage is generated during periods when no article is present and held as a constant voltage during periods when an article is present; said induced voltage and said compensated reference voltage are summed to generate a thickness voltage signal which is a measure of article thickness following a linear voltage versus thickness curve; said thickness voltage signal is compared with a pre-selected minimum level voltage signal, set by a variable voltage level means to provide a reject signal when the thickness of said article is below a pre-selected thickness level; and said reject signal is transmitted to a reject control mechanism for rejecting articles exhibiting a signal level below said pre-selected level, the improvement in said apparatus which comprises, in combination: a. a first voltage source for supplying a constant voltage; b. scaling means, connected to said thickness voltage signal, for amplifying said thickness voltage signal a pre-selected amount to obtain an output voltage signal having a numerical value substantially equal to the numerical value of the thickness of said article; c. means, connected to the output of said scaling means, for holding the minimum value of thickness of each article measured, as represented by said output voltage of said scaling means; d. visual means, connected to said means for holding the minimum value of thickness of each article measured, for representing the value of the minimum article thickness held by said means for holding the minimum value of thickness of each article measured; e. reset means, connected to said means for holding the minimum value of thicknesses of each article measured and to said first voltage source, for resetting said means for holding the minimum value of thickness of each article measured, as the measurement of a new article is started, to displace a prior minimum thickness value and accept and hold a new minimum thickness value; f. a second voltage source for supplying a constant voltage connected to said reset means; g. gate means, connected to said first and second voltage sources and to said reset means, for generating a signal to cause said reset means to operate in response to the beginning of the measurement of a new article; and h. timing means, connected to said first voltage source and said gate means, for switching said gate means on when an article is being measured and for switching said gate means off when an article is not being measured.
Claim 2
Dependent Claim
476 words
In an apparatus for measuring the thickness of an article formed from a dielectric material wherein an antenna is used to establish a radio frequency field outwardly in the direction of an article positioned adjacent thereto; a probe is positioned in said field adjacent to said article; the voltage induced in said probe is an index of the thickness of that portion of said article immediately in front of said probe; a compensated reference voltage is generated during periods when no article is present and held as a constant voltage during periods when an article is present; said induced voltage and said compensated reference voltage are summed to generate a thickness voltage signal which is a measure of article thickness following a linear voltage versus thickness curve; said thickness voltage signal is compared with a pre-selected minimum level voltage signal, set by a variable voltage level means to provide a reject signal when the thickness of said article is below a pre-selected thickness level; and said reject signal is transmitted to a reject control mechanism for rejecting articles exhibiting a signal level below said pre-selected level, the improvement in said apparatus which comprises, in combination: a. a first voltage source for supplying a constant voltage; b. scaling means, connected to said thickness voltage signal, for amplifying said thickness voltage signal a pre-selected amount to obtain an output voltage signal having a numerical value substantially equal to the numerical value of the thickness of said article; c. means, connected to the output of said scaling means, for holding the minimum value of thickness of each article measured, as represented by said output voltage of said scaling means; d. visual means, connected to said means for holding the minimum value of thickness of each article measured, for representing the value of the minimum article thickness held by said means for holding the minimum value of thickness of each article measured; e. reset means, connected to said means for holding the minimum value of thicknesses of each article measured and to said first voltage source, for resetting said means for holding the minimum value of thickness of each article measured, as the measurement of a new article is started, to displace a prior minimum thickness value and accept and hold a new minimum thickness value; f. a second voltage source for supplying a constant voltage connected to said reset means; g. gate means, connected to said first and second voltage sources and to said reset means, for generating a signal to cause said reset means to operate in response to the beginning of the measurement of a new article; and h. timing means, connected to said first voltage source and said gate means, for switching said gate means on when an article is being measured and for switching said gate means off when an article is not being measured.
Claim 3
Dependent Claim
65 words
The apparatus of claim 1, further including: switching means, connected to said gate means, said means for holding the minimum value of thickness of each article measured, said variable voltage level means, connected in circuit between said thickness voltage signal and said scaling means, for connecting either a voltage set by said variable voltage Level means or said thickness voltage signal to said scaling means.
Claim 4
Dependent Claim
62 words
The apparatus of claim 1, further including: means, connected in circuit between the output of said means for holding the minimum value of thickness of each article measured and said visual means, for limiting the represented thickness, as indicated by said output voltage of said means for holding the minimum value of thickness of each article measured, to a pre-selected maximum value.
Claim 5
Dependent Claim
122 words
The apparatus of claim 1, wherein said scaling means comprises, in combination: a. an operational amplifier having at least two input terminals and one output terminal; b. an input resistor connected to a first input terminal of said operational amplifier and to said thickness voltage signal; c. a fixed feedback resistor connected between the output terminal of said operational amplifier and said first input terminal of said operational amplifier; and d. a variable resistor connected in series with said fixed feedback resistor, the combined effect of said input resistor, said fixed feedback resistor, and said variable resistor being such that the output of said operational amplifier is a voltage which is substantially numerically equal to the thickness of an article being measured.
Claim 6
Dependent Claim
326 words
The apparatus of claim 1, wherein said means for holding the minimum value of thickness of each article measured comprises, in combination: a. a first operational amplifier having at least two input terminals and one output terminal; b. a first fixed input resistor connected in series with the output of said scaling means and to a first input terminal of said first operational amplifier; c. a second operational amplifier having at least two input terminals and one output terminal; d. a first diode, connected to said first input terminal of said first operational amplifier and to said gate means, said diode being positioned to prevent current flow therethrough when said articles are being measured and to allow current flow therethrough when said articles are not being measured; e. a second fixed input resistor connected in series with said first diode between said first diode and said first input terminal of said first operational amplifier; f. a second diode connected in series between the output terminal of said first operational amplifier and a first input terminal of said second operational amplifier, said second diode being polarized to allow passage of the output of said first operational amplifier to said second operational amplifier only if the output from said first operational amplifier represents a lesser minimum value of thickness than that represented by the output of said second operational amplifier; g. a fixed feedback resistor connected between said first input terminal of said first operational amplifier and the output terminal of said second operational amplifier; and h. a capacitor connected between said second diode and said first input terminal of said second operational amplifier and also connected to said reset means, said capacitor receiving a pre-selected voltage charge from said reset means as the measurement of an article is begun and holding the minimum thickness measured of each article, as a function of the output voltage of said first operational amplifier, until a new measurement cycle is started.
Claim 7
Dependent Claim
349 words
The apparatus of claim 1, wherein said reset means comprises, in combination: a. a monostable multivibrator having an input terminal and an output terminal, with its input terminal connected to the output of said gate means, for supplying a short duration pulse when the measurement of an article is started; b. a first transistor having a base, a collector and an emitter; c. a first resistor connected in series between the output terminal of said monostable multivibrator and the base of said first transistor, said first transistor being biased to be off so long as no current is passed by said monostable multivibrator through said first resistor; d. a second resistor connected to said first voltage supply and the emitter of said first transistor; e. a diode connected to ground and to the emitter of said first transistor for setting a bias voltage on the emitter of said first transistor; f. a second transistor having a base, a collector and an emitter; g. a third resistor connected in series between the collector of said first transistor and the base of said second transistor, said second transistor being biased to be off so long as said first transistor is off; h. a fourth resistor connected to said first voltage source and connected between said third resistor and the base of said second transistor; i. a third transistor having a base, a collector and an emitter; j. a fifth resistor connected in series between the collector of said second transistor and the base of said third transistor, said third transistor being biased to be off so long as said second transistor is off; k. means, connected to the emitter and collector of said third transistor and to said second voltage source, for connecting said second voltage source to said means for holding the minimum value of thickness of each article measured when said third transistor is on; l. a sixth resistor connected between the base of said first transistor and a ground connection; and m. a seventh resistor connected between the base of said third transistor and said second voltage supply.
Claim 8
Dependent Claim
317 words
The apparatus of claim 1, wherein said gate means comprises, in combination: a. a first resistor connected in series to said timing means; b. a first transistor, having a base, a collector and an emitter, having its base connected in series to said first resistor and its emitter connected to ground, and biased to be on only when an article is being measured; c. a second resistor connected between the base of said first transistor and a ground connection; d. a second transistor, having a base, a collector and an emitter, having its base connected to the collector of said first transistor and its emitter connected to ground, said second transistor being biased to be off when said first transistor is on; e. a third resistor connected to said first voltage source and connected in circuit between the collector of said first transistor and the base of said second transistor; f. a third transistor, having a base, a collector and an emitter, having its base connected to the collector of said second transistor, its emitter connected to said first voltage source, and its collector connected to said means for holding the minimum value of thickness of each article measured, said third transistor being biased to be off when said first transistor is on; g. a fourth resistor, connected in series between the collector of said second transistor and the base of said third transistor; h. a fifth resistor connected to said first voltage source and connected in circuit between said fourth resistor and the base of said third transistor; i. an electrical wire connected in circuit between said fourth resistor and the collector of said second transistor and connected to said reset means for carrying a signal to said reset means while an article is being measured; and j. a sixth resistor, connected to said second voltage source and connected to the collector of said third transistor.
Claim 9
Dependent Claim
265 words
The apparatus of claim 2, wherein said switching means comprises, in combination: a. an electrically operated relay having at least two pairs of contact terminals; b. a first movable switch arm, normally connected to a first one of a first pair of said two pairs of contact terminals and connected to said scaling means; c. means for connecting said first terminal of said first pair of contact terminals to said thickness voltage signal; d. means for connecting said second terminal of said first pair of contact terminals to said variable voltage level means; e. a second movable switch arm, normally connected to a first one of a second pair of said two pairs of contact terminals and connected to said means for holding the minimum value of thickness of each article measured, said first one of said second pair of contact terminals being connected to present an open circuit to said second movable switch arm; f. means for connecting said second terminal of said second pair of contact terminals to said means for holding the minimum value of thickness of each article measured; g. an operating coil within said relay for moving said switch arms from contact with said first terminals of said first and second pairs of contact terminals into contact with said second terminals of said first and second pairs of contact terminals when said operating coil is energized; and h. a normally open switch connected in series between said first voltage source and said operating coil, whereby closing said normally open switch will connect said first voltage source to said operating coil.
Claim 10
Dependent Claim
286 words
The apparatus of claim 3, wherein said means for limiting the represented thickness to a pre-selected maximum value comprises, in combination: a. an operational amplifier having at least two input terminals, one of which is connected to ground, and one output terminal connected to said visual means; b. a fixed input resistor connected in series between the output of said means for holding the minimum value of thickness of each article measured and an ungrounded input terminal of said operational amplifier; c. a fixed feedback resistor connected between the output terminal of said operational amplifier and the input of said operational amplifier to which said fixed input resistor is connected; d. a biasing voltage source having a voltage sign opposite that of the voltage output of said operational amplifier and a value greater than the maximum expected thickness of said articles as measured in terms of voltage; e. a first resistor connected to said biasing voltage source; f. a second resistor connected in series with said first resistor and connected to the output terminal of said operational amplifier; g. a diode connected to the input terminal of said operational amplifier to which said fixed input resistor is connected and connected between said first and second resistors, said diode being constrained to be nonconductive as a result of the voltage divider defined by the relative values of said first and second resistors, so long as the output voltage of said operational amplifier is below said pre-selected maximum and to be conductive so long as the output of said operational amplifier is above said pre-selected maximum value, said operational amplifier being limited and thereby incapable of any output greater than said pre-selected maximum when said diode is conductive.
Claim 11
Dependent Claim
171 words
In a method for inspecting dielectric articles wherein a radio frequency field is provided at an inspection station; an attenuated signal of said field is detected as an index of the thickness of an article placed in said field; a compensated reference signal is generated during periods when no article is present in said inspection station and held as a constant value when articles are present in said inspection station; and said attenuated signal and said compensated reference signal are summed to give an output voltage signal which is a measure of the thickness of said article following a linear voltage versus thickness curve, the improvement in said method which comprises the steps of: a. electronically scaling said thickness voltage signal to obtain a modified thickness voltage signal which is substantially numerically equal to the thickness of said article as represented by said thickness voltage signal; b. electronically holding the minimum value of said modified thickness voltage signal obtained during the inspection of each article; and c. displaying said minimum value.
Claim 12
Dependent Claim
171 words
In a method for inspecting dielectric articles wherein a radio frequency field is provided at an inspection station; an attenuated signal of said field is detected as an index of the thickness of an article placed in said field; a compensated reference signal is generated during periods when no article is present in said inspection station and held as a constant value when articles are present in said inspection station; and said attenuated signal and said compensated reference signal are summed to give an output voltage signal which is a measure of the thickness of said article following a linear voltage versus thickness curve, the improvement in said method which comprises the steps of: a. electronically scaling said thickness voltage signal to obtain a modified thickness voltage signal which is substantially numerically equal to the thickness of said article as represented by said thickness voltage signal; b. electronically holding the minimum value of said modified thickness voltage signal obtained during the inspection of each article; and c. displaying said minimum value.
Claim 13
Dependent Claim
33 words
The method of claim 10, further incLuding the step of: d. electronically erasing said held minimum value as the inspection of a new article begins to allow holding of a new minimum value.
Claim 14
Dependent Claim
27 words
The method of claim 10, further including the step of: d. constraining the display of said minimum value to no more than a pre-selected maximum thickness value.
References Cited (Backward Citations)
US3393799A
Cited
US3708064A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |