Path generating apparatus and method particularly for generating a two-lobed epitrochoid contour

Claim 2

Apparatus for displacing a tracing tool with respect to an article to trace thereon a two-lobed epitrochoid contour defined by the trace of point in a generating circle as it rolls around a base circle, the distance of the trace point from the center of the generating circle being a, the radius of the base circle being b and equal to twice the radius of the generating circle, comprising: a data input for entering data relating to a and b; an R1 circle generator generating electrical signals representing a first circular path having a radius equal to 3b/2; an R2 circle generator generating electrical signals representing a second circular path having a radius equal to a; a circle coordinator coordinating the R1 and R2 circle generators such that the angle of rotation ( Alpha 2) of the R2 circle generator signals is substantially maintained at three times the angle of rotation ( Alpha 1) of the R1 circle generator signals; and control means controlled by said R1 and R2 generator signals for controlling the relative displacement of the tracing tool with respect to said article to trace thereon the two-lobed epitrochoid contour.

Claim 3

Apparatus as defined in claim 1, wherein said displacement is effected by two drives having mutually orthogonal axes of motion, and wherein: said R1 circle generator generates a train of pulses for each axis; said R2 circle generator generates a further train of pulses for each axis; and said control means is controlled by the axispulses of the R1 and R2 generators and generates command axis-pulses supplied to the respective axis drives to trace said contour.

Claim 4

Apparatus as defined in claim 2 wherein: said data input also enters feedrate command data; said control means includes a contour generator generating in response to said R1 and R2 generator axis-pulses, a train of contour axis-pulses for each axis corresponding to the coordinates of the contour being traced; and wherein said control means further includes a velocity control system operative to compare the entered feedrate command data with the vector of said contour axis-pulses and to produce R1 feed pulses controlling the rate of pulse generation of said R1 circle generator so that the generation of the contour axis-pulses by the contour generator is at the feedrate commanded by the entered feedrate command data.

Claim 5

Apparatus as defined in claim 2, wherein said circle coordinator includes coordinating means detecting the rate of generation of the R1 generator axis-pulses and controlling in response thereto the rate of generation of R2 generator axis-pulses so that Alpha 2 3 Alpha 1.

Claim 6

Apparatus as defined in claim 4, wherein said coordinating means comprises: an error register; a sign detector detecting the sign of the error register; means effective upon the generation of an R1 generator axis pulse to increment the error rEgister in one direction by three times the sum of the X-axis and Y-axis distances of the current point on the R2 circle radius, and to generate, whenever the error register crosses zero due to that incrementing, an R2 feedpulse supplied to the R2 circle generator to produce another R2 generator axis pulse; and means effective upon the generation of an R2 generator axis-pulse to increment the error register in the opposite direction by the sum of the X-axis and Y-axis distances of the current point on the R1 circle radius, until the error register changes sign or becomes zero, such that the generation of each R1 and R2 generator axis-pulse increments the error register in the direction to approach zero.

Claim 7

Apparatus as defined in claim 1, wherein the tracing tool has a length R3 from its center to its tracing edge, said data input including means for entering data corresponding to length R3; said apparatus further comprising: an R3 circle generator generating electrical signals representing a third circular path having a radius R3; and a circle coordinator coordinating said R3 circle generator so that the radius vector of the generated R3 circle signals is always normal to the contour being traced; said control means being controlled also by said R3 circle generator signals and controlling the relative displacement of the center of the tracing tool with respect to the article to trace thereon the two-lobed epitrochoid contour.

Claim 8

Apparatus as defined in claim 6, wherein said displacement is effected by two drives having mutually orthogonal axes of motion; and wherein: said R1 circle generator generates a train of pulses for each axis; said R2 circle generator generates a further train of pulses for each axis; said R3 circle generator generates a still further train of pulses for each axis; and said control means is controlled by the axis-pulses of the R1, R2 and R3 circle generators and generates command axis-pulses supplied to the respective axis drives to trace said contour.

Claim 9

Apparatus as defined in claim 7, wherein said R3 circle coordinator includes: a tangent generator generating a train of tangent pulses for each axis representing the tangent of the contour being traced; an d coordinating means detecting the generation of said tangent axis-pulses and controlling in response thereto the generation of the R3 generator axis-pulses so that the angle ( Alpha ) with respect to one orthogonal axis formed by the radius vector of the R3 circle generator axis-pulses follows the angle ( Alpha T) with respect to the other orthogonal axis formed by the tangent to the current generated point on the contour.

Claim 10

Apparatus as defined in claim 8, wherein said R3 circle coordinating means comprises: an error register; a sign detector detecting the sign of said error register; means effective upon the generation of a tangent axis-pulse to increment said error register in one direction by the x-component of the current point on the R3 circle generator for a y-axis tangent pulse and by the y-component of the current point on the R3 circle generator for an x-axis tangent pulse, and to generate, whenever said error register is of one sign, an R3 feed pulse supplied to the R3 circle generator to produce another R3 generator axis-pulse; and means effective upon the generation of an R3 generator axis-pulse to increment said error register in the opposite direction by the x-axis distance of the current point on the tangent to the contour if a y-axis pulse had been produced and by the y-axis distance of the current point on the tangent if the R3 generator output was an x-axis pulse, until the error register changes sign or becomes zero, such that the generation of each tangent and R3 generator axis-pulse increments the error register in the direction to approach zero.

Claim 11

Apparatus for generating command axis-pulses to be supplied to two drives having mutually orthogonal axes of motion to produce a resultant displacement of a tracing tool with respect to an article to trace thereon a two-lobed epitrochoid contour defined by the trace of a point in a generating circle as it rolls around a base circle, the distance of the trace point from the center of the generating circle being a, the radius of the base circle being b and equal to twice the radius of the generating circle, comprising: a data input for entering data relating to a and b; an R1 circle generator generating a train of pulses for each axis representing a first circular path having a radius equal to 3b/2; an R2 circle generator generating a train of pulses for each axis representing a second circular path having a radius equal to a; a circle coordinator coordinating the rate of pulse generation of one of the circle generators with respect to the other such that the angle of rotation ( Alpha 2) of the R2 circle generator pulses is substantially maintained at three times the angle of rotation ( Alpha 1) of the R1 circle generator; and control means controlled by the R1 and R2 generator axis-pulses for producing command axis-pulses to be supplied to the respective axes drives for tracing said contour.

Claim 12

Apparatus for generating command axis-pulses to be supplied to two drives having mutually orthogonal axes of motion to produce a resultant displacement of a tracing tool with respect to an article to trace thereon a two-lobed epitrochoid contour defined by the trace of a point in a generating circle as it rolls around a base circle, the distance of the trace point from the center of the generating circle being a, the radius of the base circle being b and equal to twice the radius of the generating circle, comprising: a data input for entering data relating to a and b; an R1 circle generator generating a train of pulses for each axis representing a first circular path having a radius equal to 3b/2; an R2 circle generator generating a train of pulses for each axis representing a second circular path having a radius equal to a; a circle coordinator coordinating the rate of pulse generation of one of the circle generators with respect to the other such that the angle of rotation ( Alpha 2) of the R2 circle generator pulses is substantially maintained at three times the angle of rotation ( Alpha 1) of the R1 circle generator; and control means controlled by the R1 and R2 generator axis-pulses for producing command axis-pulses to be supplied to the respective axes drives for tracing said contour.

Claim 13

Apparatus as defined in claim 10, wherein the generated command axis-pulses define the tool-center path of the tool, the tool having a length R3 from its center to its tracing edge, the data input including means for entering data corresponding to length R3; the apparatus further comprising: an R3 circle generator generating a train of pulses for each axis representing a third circular path having a radius of R3; and an R3 circle coordinator coordinating the rate of pulse generation of the R3 circle generator; said R3 circle coordinator including a tangent generator generating a train of tangent pulses for each axis representing the tangent of the contour being traced and coordinating means controlling the rate of generation of the R3 generator axis-pulses so that the angle ( Alpha 3) with respect to one orthogonal axis formed by the radius vector of the R3 circle generator pulses follows the angle ( Alpha 1) with respect to the other orthogonal axis formed by the tangent to the current generated point on the contour.

Claim 14

Apparatus for generating electrical signals to control the displacement of a tool with respect to a workpiece comprising: a first circle generator generating electrical signals representing a first circular path having a radius R1; a second circle generator generating electrical signals representing a second circular path having a radius R2; and a circle coordinator including coordinating means detecting the rate of generation of the R1 generator signals and controlling in response thereto the rate of generation of the R2 generator signals such that the angle of rotation ( Alpha 2) of the R2 circle generator signals is substantially maintained at a multiple of n times the angle of rotation ( Alpha 1) of the R1 circle generator signals.

Claim 15

Apparatus for generating electrical signals to control the displacement of a tool with respect to a workpiece comprising: a first circle generator generating electrical signals representing a first circular path having a radius R1; a second circle generator generating electrical signals representing a second circular path having a radius R2; and a circle coordinator including coordinating means detecting the rate of generation of the R1 generator signals and controlling in response thereto the rate of generation of the R2 generator signals such that the angle of rotation ( Alpha 2) of the R2 circle generator signals is substantially maintained at a multiple of n times the angle of rotation ( Alpha 1) of the R1 circle generator signals.

Claim 16

Apparatus as defined in claim 12, wherein the tool is displaceable with respect to the X and Y axes, and wherein said circle generators each generates a train of axis-pulses for each of the X and Y axes.

Claim 17

Apparatus as defined in claim 13, wherein said coordinating means comprises: an error register; a sign detector detecting the sign of the error register; means effective upon the generation of an R1 generator axis-pulse to increment the error register in one direction by n times the sum of the X-axis and Y-axis distances of the current point on the R2 circle radius, and to generate, whenever the error register is of one sign, a feed pulse applied to the R2 circle generator to produce another R2 generator axis-pulse; and means effective upon the generation of an R2 generator axis-pulse to increment the error register in the opposite direction by the sum of the X-axis and Y-axis distances of the current point on the R1 circle radius, until the error register changes sign or becomes zero, such that the generation of each R1 and R2 generator axis-pulse always increments the error register in the direction to approach zero.

Claim 18

Apparatus for generating drive electrical signals to be supplied to drive means to produce a resultant movement of a tracing tool with respect to an article to trace thereon a specific contour, the tracing tool having a length R from its center to its tracing edge, comprising: a contour generator generating contour electrical signals representing the contour to be traced; a circle generator generating further electrical signals representing a circular path having a radius R; a circle coordinator continuously receiving the contour electrical signals from the contour generator and coordinating the circle generator so that the radius vector of the generated circle signals is always normal to the contour being traced; and a tool-center path signal generator utilizing both said contour electrical signals and further electrical signals to produce motion command electrical signals defining the path the center of the tool is to take in order to trace said contour at its tracing edge.

Claim 19

Apparatus for generating drive electrical signals to be supplied to drive means to produce a resultant movement of a tracing tool with respect to an article to trace thereon a specific contour, the tracing tool having a length R from its center to its tracing edge, comprising: a contour generator generating contour electrical signals representing the contour to be traced; a circle generator generating further electrical signals representing a circular path having a radius R; a circle coordinator continuously receiving the contour electrical signals from the contour generator and coordinating the circle generator so that the radius vector of the generated circle signals is always normal to the contour being traced; and a tool-center path signal generator utilizing both said contour electrical signals and further electrical signals to produce motion command electrical signals defining the path the center of the tool is to take in order to trace said contour at its tracing edge.

Claim 20

Apparatus as defined in claim 15, wherein said circle coordinator includes: a tangent generator continuously receiving the contour electrical signals from the contour generator and generating tangent electrical signals representing the tangent of the contour being traced.

Claim 21

Apparatus as defined in claim 16, wherein said drive means includes two drives having mutually orthogonal axes of motion, and wherein each of said generators generates a train of pulses for each of said two axes.

Claim 22

Apparatus as defined in claim 17, wherein said circle coordinator further includes coordinating means detecting the generation of the axis-pulses by the tangent generator and controlling in response thereto the generation of the circle generator axis-pulses so that the angle with respect to one orthogonal axis formed by the radius vector of the circle generator axis-pulses follows the angle with respect to the other orthogonal axis formed by the tangent to the current generated point on the contour.

Claim 25

The method as defined in claim 19, wherein the tracing tool has a length R3 from its center to its tracing edge, the method further comprising: generating R3 electrical signals representing a third circular path having a radius equal to R3; coordinating the generation of the R3 electrical signals so that the radius vector of the generated R3 circle is always normal to the contour being traced; and utilizing said R3 electrical signals in addition to said R1 and R2 electrical signals, for controlling the relative displacement of the tool-center with respect to the article to cause the tracing edge of the tool to trace said two-lobed epitrochoid contour on the article.

Claim 26

The method as defined in claim 20, wherein the electrical signals generated are each in the form of a train of pulses for the X-axis and a train of pulses for the Y-axis.

Claim 27

The method as defined in claim 21, wherein the coordinating of the generation of the R3 electrical signals is effected by generating tangent electrical signals in the form of a pulse train for each axis representing the tangent of the contour being traced, detecting the generation of the tangent axis-pulses, and controlling in response thereto the generation of the R3 axis-pulses so that the angle with respect to one axis formed by the radius vector of the R3 circle axis-pulses follows the angle with respect to the other axis formed by the tangent axis-pulses.