Pattern contour tracing apparatus

Claim 2

A photosensitive arrangement carried by a movable scanning head for controlling the position of said head relative a contour line defining either a pattern edge or a drawing line, the improvement comprising a first pair of photosensitive cells carried by said head with each cell having an equal light sensitive area of triangular configuration for movement with said head into a position overlapping said line, one cell triangular area defined by an isosceles triangle and the other cell triangular area defined by two right triangles each having a hypotenuse adjacent and substantially coextensive with a respective one of the equal legs of said isosceles triangle, and means for projecting an image of said line on said cells in response to movement of said celLs into said overlapping position whereby said cells provide equal output signals in response to the projected image of said line dividing each area into equal portions and unequal output signals in response to the projected image of said line dividing each area into unequal portions.

Claim 3

The photosensitive arrangement claimed in claim 1 in which said head is rotatable by one motor to maintain said head in a predetermined angular position relative said line and said head is moved longitudinally along said line by a pair of coordinate drive motors, the improvement comprising a second pair of said cells each having an area of triangular configuration corresponding to a respective one of said first cells and said head has an axis of rotation lying between said first and second pairs of cells and along a line bisecting each triangular area, first means for combining the output signal from each cell of said one pair with a signal from each respective cell of the other pair for determining the displacement of said line image from said bisecting line, and second means for combining the output signal from each cell of said one pair with a signal from each respective other cell of the other pair for deriving a first signal corresponding to the angular orientation of said image relative said axis at a position spaced from said axis along the direction of head movement.

Claim 4

In the arrangement claimed in claim 2, a pair of serially connected resistors with one of said resistors connected to said means for combining said signals to derive a first signal corresponding to the angular orientation, an amplifier having an input connected to the other one of said resistors and an output connected to said one motor for rotating said head, normally ineffective means connected between said resistors for reducing the signal applied to said amplifier from said resistors for reducing the rate at which said one motor rotates said head, and manually operable means for rendering said ineffective means effective to reduce the signal applied from said resistors to said amplifier input for reducing said rate of rotation.

Claim 5

In the arrangement claimed in claim 2, a third pair of cells each having an area of triangular configuration corresponding to a respective one of said first and second pair of cells with said second pair of cells spaced intermediate said first and third pair of cells, means for combining the output signal of each cell of said first pair of cells with the output signal of a cell of said third pair to derive a second signal corresponding to the angular orientation of said image relative said axis at a position spaced from said axis along the direction of movement, and manually operable means for connecting either said first signal or said second signal to said one motor for rotating said head in accordance with the speed of said coordinate drive motors.

Claim 6

In the arrangement claimed in claim 2, an additional pair of cells of equal area each spaced adjacent a respective end of said first cell pair in a direction transverse to said line image, means for combining the outputs of said additional pair of cells with each other, means for combining the outputs of said first pair of cells with each other, and means for combining the combined signals of said additional and first pairs of cells for driving said coordinate motors in response to said contour line defining a pattern edge with one cell of said additional pair of cells overlapping the pattern forming said edge.

Claim 7

In the arrangement claimed in claim 5, means for combining the outputs of said second pair of cells with each other and with the combined signal of said first pair of cells for determining the angular orientation of said pattern edge relative said axis.

Claim 8

In the arrangement claimed in claim 6, a start relay operated for initiating control of said motors by said cells, manually operable means for selecting the combined outputs of said additional and first pair of cells for operating said start relay in response to saId contour line defining a drawing line, and manually operable means for selecting the combined outputs of each cell of said first pair with a respective cell of said second pair to determine line displacement for operating said start relay in response to said contour line defining a pattern edge.

Claim 9

In a scanning system of the type having a scanning head carrying a plurality of light sensitive cells for sensing the presence of a contour line, a steering head motor for rotating said head and cells in response to a signal from said cells for enabling said cells to be positioned in overlapping relationship to said contour line and at a predetermined angle to said contour line from a position offset from said line for thereafter following said line at said angle, a pair of coordinate drive motors for moving said head to and longitudinally along said line under control of said steering head motor, an amplifier for amplifying the signal derived from said cells for application to said steering motor, a pair of serially connected resistors for transmitting said signal to said amplifier for enabling said amplifier to control said steering motor to rotate said head and cells to said predetermined angle in response to said cells being moved from said offset position to one overlapping position relative said line, normally ineffective means connected between said resistors for reducing the signal provided to said amplifier for reducing the rate of rotational movement of said steering head motor during movement of said head from said offset position into said one overlapping position, and manually operated means operated for rendering said normally ineffective means effective to reduce said signal during movement from said offset position to said one overlapping position and thereafter restored to render said signal reducing means ineffective.

Claim 10

In a scanning system of the type having a scanning head carrying a plurality of light sensitive cells for sensing the presence of a contour line, a steering head motor for rotating said head and cells in response to a signal from said cells for enabling said cells to be positioned in overlapping relationship to said contour line and at a predetermined angle to said contour line from a position offset from said line for thereafter following said line at said angle, a pair of coordinate drive motors for moving said head to and longitudinally along said line under control of said steering head motor, an amplifier for amplifying the signal derived from said cells for application to said steering motor, a pair of serially connected resistors for transmitting said signal to said amplifier for enabling said amplifier to control said steering motor to rotate said head and cells to said predetermined angle in response to said cells being moved from said offset position to one overlapping position relative said line, normally ineffective means connected between said resistors for reducing the signal provided to said amplifier for reducing the rate of rotational movement of said steering head motor during movement of said head from said offset position into said one overlapping position, and manually operated means operated for rendering said normally ineffective means effective to reduce said signal during movement from said offset position to said one overlapping position and thereafter restored to render said signal reducing means ineffective.