Title: Incremental measuring instrument

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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Inventors: Ernst, Alfons (Traunreut, DE, US)

Application Number: 971245
Filing Date: 1978-12-20
Publication_date: 1981-02-24
Assignee: Dr. Johannes Heidenhain GmbH (Traunreut, DE)
Primary Class(es): 250/231.14 250/237G
Other Classes:
US Patent Ref:

2524807	Oct, 1950	Kallmann.
2565745	Aug, 1951	Shalka.
3153111	Oct, 1964	Barber et al.	250/237.
3254226	May, 1966	Bobula et al.
3757128	Sep, 1973	Vermeulen	250/237.
3935447	Jan, 1976	Black et al.	250/231.
3950096	Apr, 1976	Aeschlimann et al.
4171160	Oct, 1979	Ernst.

Other Refs: 118014611773531202012215781324482192302512

May, 1957	DE.
Jun, 1959	DE.
Sep, 1965	DE.
May, 1973	DE.
Apr, 1976	DE.
Sep, 1976	FR.

Primary Examiner: Nelms, David C.
Assistant Examiner: Hostetter, Darwin R.
Attorney: Hume, Clement, Brinks, Willian & Olds, Ltd.