Pattern catching in a photoelectric pattern contour tracing system

Claim 2

A pattern contour-tracing system comprising a rotatable pattern sensing head having a front-to-back axis, means for driving the sensing head in the direction of the front-to-back axis, means for automatically rotating the sensing head responsive to deviations of the position of said sensing head from said contour to cause said sensing head to follow said pattern contour, control means for causing the sensing head to catch the contour from a position off of the contour, said control means comprising means for pointing the front-to-back axis toward the contour, means including said drive means for causing said sensing head to approach the pattern, means for detecting when the sensing head reaches a position a predetermined distance from the contour, and means responsive to said detecting means for preventing the operation of said automatic rotating means until the sensing head reaches said predetermined distance position.

Claim 3

In the pattern contour-tracing system of claim 1 wherein said sensing head comprises sensing means for producing an electrical signal the amplitude of which is indicative of the transverse deviation of said sensing head from the contour, and wherein said detecting means operates responsive to said electrical signal.

Claim 4

In the system of claim 2 wherein said sensing means are adapted to produce an electrical signal the amplitude of which approaches a first predetermined level as the sensing head approaches the pattern contour, and wherein said detecting means causes said preventing means to maintain said automatic rotating means inoperable until the amplitude of said electrical signal is within a predetermined range of said first predetermined level, the amplitude level of the outer limit of said predetermined range being representative of said predetermined distance.

Claim 5

In the system of claim 3 wherein said detecting means comprises means operable responsive only to an electric signal which reaches said outer limit amplitude level from a level outside of said predetermined range to disenable said preventing means to activate said rotating means.

Claim 6

In the system of claim 4 wherein said disenabling means comprises a memory cell operable responsive only to an electric signal amplitude level outside of said predetermined range and a gate operable responsive to the operation of said memory cell and the subsequent attainment of said outer limit amplitude level the output of which controls said preventing means.

Claim 7

In the system of claim 2 wherein said sensing means is adapted to produce an electric signal the absolute amplitude of which drops toward a minimum as the sensing head approaches the contour, and wherein said detecting means causes said preventing means to maintain said automatic rotating means inoperable until the amplitude of said electrical signal drops below a predetermined amplitude level above said minimum representative of said predetermined distance.

Claim 8

In the system of claim 6 wherein said detecting means comprises means operable responsive only to a decreasing absolute amplitude signal to said predetermined level for disenabling said preventing means to activate said rotating means.

Claim 9

In the system of claim 7 wherein said disenabling means comprises a memory cell operable responsive only to an absolute amplitude signal greater than said predetermined level and a gate operable responsive to the operation of said memory cell and the subsequent attainment of said predetermined absolute amplitude level signal the output of which controls said preventing means.

Claim 10

A pattern contour-tracing system comprising a sensing head rotatable about an axis and having a front-to-back axis, means for driving said head in the direction of said front-to-back axis, photosensitive means in said head, means for projecting an image of a portion of said pAttern forward of said rotational axis on said photosensitive means to cause same to produce electrical signals indicative of deviations of said photosensitive means from the image of said pattern contour, means for automatically rotating said sensing head toward said contour responsive to said electrical signals to cause same to follow said contour, and control means for causing the sensing head to automatically catch and follow said contour from a position off of said contour, said control means comprising means for pointing the front-to-back axis toward the pattern contour, means including said driving means for causing said sensing head to approach the pattern, means including said photosensitive means for detecting when the sensing head reaches a position a predetermined distance from the contour, and means responsive to said detecting means for preventing the operation of said automatic rotating means until the sensing head reaches said predetermined distance position.

Claim 11

A pattern contour-tracing system comprising a sensing head rotatable about an axis and having a front-to-back axis, means for driving said head in the direction of said front-to-back axis, photosensitive means in said head, means for projecting an image of a portion of said pAttern forward of said rotational axis on said photosensitive means to cause same to produce electrical signals indicative of deviations of said photosensitive means from the image of said pattern contour, means for automatically rotating said sensing head toward said contour responsive to said electrical signals to cause same to follow said contour, and control means for causing the sensing head to automatically catch and follow said contour from a position off of said contour, said control means comprising means for pointing the front-to-back axis toward the pattern contour, means including said driving means for causing said sensing head to approach the pattern, means including said photosensitive means for detecting when the sensing head reaches a position a predetermined distance from the contour, and means responsive to said detecting means for preventing the operation of said automatic rotating means until the sensing head reaches said predetermined distance position.

Claim 12

In the system of claim 9 wherein said photosensitive means are adapted to produce an electric signal the amplitude of which approaches a first predetermined level as the sensing head approaches the pattern contour, and wherein said detecting means causes said preventing means to maintain said automatic rotating means inoperable until the amplitude of said electric signal is within a predetermined range of said first predetermined level, the amplitude level of the outer limits of said predetermined range being representative of said predetermined distance.

Claim 13

In the system of claim 10 wherein said detecting means comprises means operable responsive only to an electric signal which reaches said outer limit amplitude level from a level outside of said predetermined range for disenabling said preventing means to activate said rotating means.

Claim 14

In the system of claim 11 wherein said disenabling means comprises a memory cell operable responsive only to an electric signal amplitude level outside of said predetermined range and a gate operable responsive to the operation of said memory cell and the subsequent attainment of said outer limit amplitude level, the output of which controls said preventing means.

Claim 15

In the system of claim 9 wherein said photosensitive means is adapted to produce an electric signal the absolute amplitude of which drops toward a minimum as the sensing head approaches the contour, and wherein said detecting means causes said preventing means to maintain said automatic rotating means inoperable until the amplitude of said electrical signal drops below a predetermined amplitude level above said minimum representative of said predetermined distance.

Claim 16

In the system of claim 13 wherein said detecting means comprises means operable responsive only to a decreasing absolute amplitude signal to said predetermined level for disenabling said preventing means to activate said rotating means.

Claim 17

In the system of claim 14 wherein said disenabling means comprises a memory cell operable responsive only to an absolute amplitude signal greater than said predetermined level and a gate operable responsive to the operation of said memory cell and the subsequent attainment of said predetermined absolute amplitude level signal the output of which controls said preventing means.

Claim 18

In the system of claim 9 in which said pattern contour is a line and wherein said photosensitive means is adapted to scan the image of said pattern across a centerline of scan corresponding to said front-to-back axis at a reference frequency to produce a fluctuating signal, said electrical signal being a reference frequency component of said fluctuating signal which is present whenever an image of said pattern is being scanned except when the centerline of scan is aligned with the image of said pattern line.

Claim 19

In the system of claim 13 in which said pattern contour is a line and wherein said photosensitive means is adapted to scan the image of said pattern across a centerline of scan corresponding to sAid front-to-back axis at a reference frequency to produce a fluctuating signal, said electrical signal being a reference frequency component of said fluctuating signal which is present whenever an image of said pattern is being scanned except when the centerline of scan is aligned with the image of said pattern line.

Claim 20

In the system of claim 15 in which said pattern contour is a line and wherein said photosensitive means is adapted to scan the image of said pattern across a centerline of scan corresponding to said front-to-back axis at a reference frequency to produce a fluctuating signal, said electrical signal being a reference frequency component of said fluctuating signal which is present whenever an image of said pattern is being scanned except when the centerline of scan is aligned with the image of said pattern line.

Claim 21

In the system of claim 9 in which said pattern contour is an edge formed on the pattern between two contrasting colors, and wherein said photosensitive means is adapted to scan said edge at a reference frequency to produce a fluctuating signal, said electrical signal being a reference frequency component of said fluctuating signal which is present when said photosensitive means is not aligned with said edge and is absent when said photosensitive means is aligned with said edge.

Claim 22

In the system of claim 13 in which said pattern contour is an edge formed on the pattern between two contrasting colors, and wherein said photosensitive means is adapted to scan said edge at a reference frequency to produce a fluctuating signal, said electrical signal being a reference frequency component of said fluctuating signal which is present when said photosensitive means is not aligned with said edge and is a absent when said photosensitive means is aligned with said edge.

Claim 23

In the system of claim 15 in which said pattern contour is an edge formed on the pattern between two contrasting colors, and wherein said photosensitive means is adapted to scan said edge at a reference frequency to produce a fluctuating signal, said electrical signal being a reference frequency component of said fluctuating signal which is present when said photosensitive means is not aligned with said edge and is absent when said photosensitive means is aligned with said edge.