Method and apparatus for measuring a dimension of an object

Claim 5

Method of measuring a linear dimension of an object, comprising: generating first and second rotating lines of sight for scanning the dimension to b measured, these two lines of sight being parallel to each other and having their centers of rotation spaced apart by a determined distance in a direction parallel to said dimension; scanning the object with said lines of sight; detecting the two images of said transmitted respectively by the scanning of these two lines of sight; generating from each said detection, a pulse burst consisting of a train of digital pulses, the value of said pulse burst being proportional to said dimension, the two pulse bursts being equal in value but having leading and trailing edges shifted in time by a time-shift which Is substantially proportional to the spacing, in said direction parallel to said dimension, of the two centers of rotation at approximately the times said leading and trailing edges occur, the constant of proportionality of the time-shift to the spacing being the same as the constant of proportionality of the pulse bursts to said dimension, this common constant of proportionality being susceptible to vary from one measurement to another; and forming the quotient of one of the pulse bursts and of their time-shift to eliminate the common constant proportionality, this quotient then being proportional to the linear dimension to be measured, by a constant of proportionality that is less susceptible than said common constant of proportionality to vary from one measurement to another.

Claim 6

Method of measuring a linear dimension of an object, comprising: generating first and second rotating lines of sight for scanning the dimension to b measured, these two lines of sight being parallel to each other and having their centers of rotation spaced apart by a determined distance in a direction parallel to said dimension; scanning the object with said lines of sight; detecting the two images of said transmitted respectively by the scanning of these two lines of sight; generating from each said detection, a pulse burst consisting of a train of digital pulses, the value of said pulse burst being proportional to said dimension, the two pulse bursts being equal in value but having leading and trailing edges shifted in time by a time-shift which Is substantially proportional to the spacing, in said direction parallel to said dimension, of the two centers of rotation at approximately the times said leading and trailing edges occur, the constant of proportionality of the time-shift to the spacing being the same as the constant of proportionality of the pulse bursts to said dimension, this common constant of proportionality being susceptible to vary from one measurement to another; and forming the quotient of one of the pulse bursts and of their time-shift to eliminate the common constant proportionality, this quotient then being proportional to the linear dimension to be measured, by a constant of proportionality that is less susceptible than said common constant of proportionality to vary from one measurement to another.

Claim 7

Method according to claim 3, in which the angle scanned on the object is sufficiently small to be approximated by its tangent, and wherein the first and second lines of sight scan the object at constant angular velocity, and wherein said pulse bursts are generated such that their value is proportional to the duration of the detection of the object images and hence proportional to the angle scanned and hence approximately proportional to the linear dimension to be measured.

Claim 8

Apparatus for measuring a linear dimension of an object comprising radiation-reflecting means for generating a plurality of parallel object sight lines spaced apart a substantially constant distance along a direction generally parallel to the object dimension under measurement, means for rotating said reflector means so that said sight lines sweep across the object in the direction of said dimension, means responsive to object images circumscribed by each of said lines for producing two electrical pulses of substantially equal time durations proportional to the object''s dimension and time delayed relative to one another by a time interval proportional to the said distance between said lines, and means coupled to the pulse producing means for computing the magnitude of the object dimension from the time duration of said pulses and the time interval of the time delay.

Claim 9

Apparatus for measuring a linear dimension of an object comprising radiation-reflecting means for generating a plurality of parallel object sight lines spaced apart a substantially constant distance along a direction generally parallel to the object dimension under measurement, means for rotating said reflector means so that said sight lines sweep across the object in the direction of said dimension, means responsive to object images circumscribed by each of said lines for producing two electrical pulses of substantially equal time durations proportional to the object''s dimension and time delayed relative to one another by a time interval proportional to the said distance between said lines, and means coupled to the pulse producing means for computing the magnitude of the object dimension from the time duration of said pulses and the time interval of the time delay.

Claim 10

Apparatus for measuring the dimensions of an article comprising, at least two elongated parallel radiation-reflective surfaces mounted for concentric rotation about an axis, said surfaces being spaced apart in the direction of said axis, and positioned different radial distances from said axis, means for concurrently rotating said surfaces about said axis, said surfaces being spaced from the article to reflect images of said article as said surfaces rotate through an arc, a plurality of matched radiation detectors mounted in juxtaposed relationship to receive said images from said surfaces and responsive thereto for producing sequential electrical pulses of pulse width corresponding to the angle circumscribed by said arc, said pulses being shifted relative to one another in the time domain by an amount determined at least in part by said radial distances, means for timing the pulse width of one of said electrical pulses and of the amount of pulse shift, and means coupled to said means for timing for generating a quotient signal representative of the magnitude of said dimension from the time duration of said electrical pulse and the time interval of said pulse shift.

Claim 11

Apparatus for measuring the dimensions of an article comprising, at least two elongated parallel radiation-reflective surfaces mounted for concentric rotation about an axis, said surfaces being spaced apart in the direction of said axis, and positioned different radial distances from said axis, means for concurrently rotating said surfaces about said axis, said surfaces being spaced from the article to reflect images of said article as said surfaces rotate through an arc, a plurality of matched radiation detectors mounted in juxtaposed relationship to receive said images from said surfaces and responsive thereto for producing sequential electrical pulses of pulse width corresponding to the angle circumscribed by said arc, said pulses being shifted relative to one another in the time domain by an amount determined at least in part by said radial distances, means for timing the pulse width of one of said electrical pulses and of the amount of pulse shift, and means coupled to said means for timing for generating a quotient signal representative of the magnitude of said dimension from the time duration of said electrical pulse and the time interval of said pulse shift.

Claim 12

The apparatus as claimed in claim 6 which further comprises elongated illuminated scale means positioned generally parallel to the object dimension and including spaced-apart indicia representing article dimensions, third and fourth reflective surfaces positioned similar to said first and second surfaces respectively and mounted between said scale means and the article for rotation about said axis in synchronism with said first and second surfaces, said third and fourth surfaces facing said scale means when said first and second surfaces are reflecting said images of the article, and photoelectric detection means positioned to receive reflected images of said indicia for generating Corrective electrical signals for the quotient signal generating means.

Claim 13

Apparatus for measuring the linear dimension of a radiating object comprising, two polygonal mirrors spaced from the object and mounted in juxtaposed relationship for rotation about a common central axis, said mirrors having mutually parallel radiation-reflecting surfaces disposed different radial distances from said axis, means for rotating said mirrors concurrently, and two radiation-responsive devices disposed adjacent one another and positioned to receive radiation from said object reflected by the reflecting surfaces of said respective mirrors, each of said devices producing an output pulse having a pulse width corresponding to the object dimension under measurement, one of said output pulses being time delayed relative to the other an amount corresponding to the said distance between said two reflecting surfaces, and means coupled to the outputs of said devices for computing the magnitude of the dimension from the pulse width of said one output pulse and the time delay thereof.

Claim 14

Apparatus for measuring the linear dimension of a radiating object comprising, two polygonal mirrors spaced from the object and mounted in juxtaposed relationship for rotation about a common central axis, said mirrors having mutually parallel radiation-reflecting surfaces disposed different radial distances from said axis, means for rotating said mirrors concurrently, and two radiation-responsive devices disposed adjacent one another and positioned to receive radiation from said object reflected by the reflecting surfaces of said respective mirrors, each of said devices producing an output pulse having a pulse width corresponding to the object dimension under measurement, one of said output pulses being time delayed relative to the other an amount corresponding to the said distance between said two reflecting surfaces, and means coupled to the outputs of said devices for computing the magnitude of the dimension from the pulse width of said one output pulse and the time delay thereof.

Claim 15

Apparatus for measuring a linear dimension of an object, comprising: means for generating a first and a second rotating line of sight for scanning the object along the dimension to be measured, these two lines of sight being parallel to each other and having their centers of rotation spaced apart by a determined distance in a direction parallel to said dimension; means for detecting the two images of said object transmitted respectively by these two lines of sight; means for generating, from each said detection, a pulse burst consisting of a train of digital pulses, the value of said pulse burst being proportional to said dimension, the two pulse bursts being equal in value but having leading and trailing edges shifted in time by a time-shift which is substantially proportional to the spacing, in said direction parallel to said dimension, of the two centers of rotation at approximately the times said leading and trailing edges occur, the constant of proportionality of the time-shift to the spacing being the same as the constant of proportionality of the pulse bursts to said dimension, this common constant of proportionality being susceptible to vary from one measurement to another; and means for forming the quotient of one of the pulse bursts and of their time-shift to eliminate the common constant of proportionality, this quotient then being proportional to the linear dimension to be measured, by a constant of proportionality that is less susceptible than said common constant of proportionality to vary from one measurement to another.

Claim 16

Apparatus for measuring a linear dimension of an object, comprising: means for generating a first and a second rotating line of sight for scanning the object along the dimension to be measured, these two lines of sight being parallel to each other and having their centers of rotation spaced apart by a determined distance in a direction parallel to said dimension; means for detecting the two images of said object transmitted respectively by these two lines of sight; means for generating, from each said detection, a pulse burst consisting of a train of digital pulses, the value of said pulse burst being proportional to said dimension, the two pulse bursts being equal in value but having leading and trailing edges shifted in time by a time-shift which is substantially proportional to the spacing, in said direction parallel to said dimension, of the two centers of rotation at approximately the times said leading and trailing edges occur, the constant of proportionality of the time-shift to the spacing being the same as the constant of proportionality of the pulse bursts to said dimension, this common constant of proportionality being susceptible to vary from one measurement to another; and means for forming the quotient of one of the pulse bursts and of their time-shift to eliminate the common constant of proportionality, this quotient then being proportional to the linear dimension to be measured, by a constant of proportionality that is less susceptible than said common constant of proportionality to vary from one measurement to another.

Claim 17

Apparatus according to claim 9, wherein said means for generating a first and a second line of sight comprise two plane, parallel, rotary mirrors rotatable about an axis which is perpendicular to said dimension and offset to the same side of both said plane mirrors, and wherein said means for detecting the two object images are directed respectively at said plane mirrors in directions parallel to the dimension to be measured.