US 5,121,550 AGranted

Automatic surface tracer

AssigneeGerber Optial, Inc.

InventorsKenneth O. Wood, Jeffrey Murray, Robert J. Pavone

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Abstract

A device for tracing a surface such as one defining the lens opening of an eyeglass frame includes a tracer element moved automatically about a rotational axis surrounded by the traced surface and arranged perpendicularly to the area enclosed by the surface. As this rotation occurs a carrier for the tracer element is moved along a second axis extending perpendicularly to the rotational axis in response to a position error signal developed by the tracer element to maintain the position error signal at a substantially zero value through the use of feedback circuitry. The positions of the carrier about the rotational axis and along the second axis are repeatedly captured during the tracing movement to provide point data defining the shape of the traced surface. Results are a smooth steady movement of the tracer element along the surface with a minimum amount of force being exerted on the traced surface by the tracer element.

Claims14

Dependent claims

A device for providing data describing the shape of an at least substantially closed surface, said device comprising:

a first structure,
a holder for releasably holding a member providing a closed surface such as aforesaid,
means supporting said holder for movement of said holder and said first structure relative to one another about a rotational axis fixed relative to said first structure and passing through and oriented generally perpendicularly to the area enclosed by said closed surface of said member held by said holding means,
drive means for rotating said holder and said first structure relative to one another about said rotational axis,
a carrier,
means supporting said carrier for movement relative to said first structure along a second axis fixed relative to said first structure and extending generally perpendicularly to said rotational axis so that said second axis and carrier move angularly relatively to said closed surface in unison with the movement of said first structure and holder relative to one another about said rotational axis,
means for moving said carrier in both directions along said second axis,
a sensor carried by said carrier and operable to produce a signal which varies substantially linearly with the displacement of a reference point on said carrier from said closed surface in a direction parallel to said second axis throughout a sensing zone located in the proximity of said closed surface,
means responsive to the signal produced by said sensor for operating said carrier moving means to so position said carrier along said second axis as to maintain the displacement of said reference point from said closed surface as measured parallel to said second axis at a substantially constant value as said holder and first structure are rotated relative to one another about said rotational axis, and
means operable as said holder and first structure are rotated relative to one another about said first axis for at successive instants of time sensing and outputting data signals defining for each instant the angular position of said holder relative to said first structure about said rotational axis and the position of said carrier along said second axis.

7 more elements

A device for providing data describing the shape of a closed surface used as a reference for the edging of an eyeglass lens to cause it to fit into a given lens opening in an eyeglass frame, said device comprising:

a stationary base structure,
a rotatable structure supported by said base structure for rotation relative to said base structure about a rotational axis fixed relative to said base structure,
drive means for rotating said rotatable structure about said rotational axis relative to said base structure,
a holder for releasably holding a member providing a closed surface such as aforesaid fixed relative to said base structure, said holder being so positioned on said base structure that the closed surface of a member held by said holder surrounds said rotational axis and so that the area enclosed by said closed surface is generally perpendicular to said rotational axis,
a carrier supported on said rotatable structure for movement relative to said rotatable structure along a second axis fixed relative to said rotatable structure and extending perpendicularly of said rotational axis,
a stylus carried by said carrier and having an engagement part for engaging the closed surface of a member held by said holder,
means supporting said stylus on said carrier for movement of said stylus relative to said carrier in such a manner that said engagement part of said stylus is moveable along a line generally parallel to said second axis between first and second end positions relative to said carrier,
means for biasing said stylus relative to said carrier so that said engagement part of said stylus is resiliently urged toward one of said end positions,
said engagement part of said stylus as a result of rotation of said rotatable structure about said rotational axis being swept along the length of said closed surface,
a position error sensor for detecting the deviation in either direction of said engagement part of said stylus from a given neutral position located between said end positions in its movement relative to said carrier and for producing a signal relative to said deviation,
means responsive to said position error sensor signal as said rotatable structure is rotated about said rotational axis for moving said carrier along said second axis relative to said rotatable structure to cause said stylus engagement part to be maintained substantially at said neutral position relative to said carrier, and
means operable as said rotatable structure is rotated about said rotational axis for at successive instants of time sensing and outputting data signals defining for each instant the angular position of said rotatable structure relative to said base structure about said rotational axis and the position of said carrier relative to said rotatable structure along said second axis.

9 more elements

Dependencies are inferred from the claim text.