Incremental measuring instrument
First Claim
1. In an instrument for measuring the movement of a first object with respect to a second object along a measuring direction, said instrument including first means, mounted on the first object, for defining a rotatable first pattern of spirally formed stripes, second means mounted on the second object, for defining a second pattern of stripes oriented substantially perpendicularly to the measuring direction, means for generating an optical image of one of said patterns on the other of said patterns at an image zone, means for generating a measurement signal representative of the intensity of light given off from said other pattern, means for generating a reference signal, and means for evaluating the measurement signal in comparison with the reference signal, the improvement comprising:
- the stripes of the rotatable spirally striped pattern are formed substantially in the form of involutes proceeding from a base circle centered at the center of rotation of the spirally striped pattern; and
said means for generating an optical image includes means for orienting the stripes of the second pattern substantially perpendicular to a line tangent to the base circle passing through the image zone;
said means for generating an optical image operating to generate a reduced image of said one pattern on said other pattern.
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Accused Products
Abstract
An instrument for measuring the movement of a first object with respect to a second object is disclosed including a rotatable opaque disc mounted on the first object, which disc defines a plurality of translucent involute stripes proceeding from a base circle, a scale including a reflective grid pattern mounted on the second object, and an optical system for projecting an image of a portion of the grid pattern onto an image zone of the disc such that the stripes of the image of the grid are substantially perpendicular to a line drawn tangent to the base circle through the image zone.
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Citations
24 Claims
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1. In an instrument for measuring the movement of a first object with respect to a second object along a measuring direction, said instrument including first means, mounted on the first object, for defining a rotatable first pattern of spirally formed stripes, second means mounted on the second object, for defining a second pattern of stripes oriented substantially perpendicularly to the measuring direction, means for generating an optical image of one of said patterns on the other of said patterns at an image zone, means for generating a measurement signal representative of the intensity of light given off from said other pattern, means for generating a reference signal, and means for evaluating the measurement signal in comparison with the reference signal, the improvement comprising:
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the stripes of the rotatable spirally striped pattern are formed substantially in the form of involutes proceeding from a base circle centered at the center of rotation of the spirally striped pattern; and said means for generating an optical image includes means for orienting the stripes of the second pattern substantially perpendicular to a line tangent to the base circle passing through the image zone; said means for generating an optical image operating to generate a reduced image of said one pattern on said other pattern. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15)
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13. An instrument for optically measuring the movement of a first object with respect to a second object along a measuring direction, said instrument comprising:
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a disc defining a first pattern including a plurality of involute shaped stripes, each of which proceeds from a base circle centered at a rotation point; means for rotatably mounted the disc to the first object such that the disc is rotatable about the rotation point; a scale defining a second pattern including a plurality of stripes; means for mounting the scale to the second object such that the plurality of stripes are substantially perpendicular to the measuring direction; means for generating a reduced optical image of one of said patterns on the other of said patterns at an image zone; means for generating a measurement signal representative of the intensity of light given off from at least a portion of said image zone; means for generating a reference signal; and means for evaluating the measurement signal in comparison with the reference signal. - View Dependent Claims (14, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification