Refractometer

The ornamental design for a refractometer, as shown and described.

FIG. 1 is a right side elevation of a refractometer, showing my new design;

FIG. 2 is a left side elevation thereof;

FIG. 3 is a front elevation thereof;

FIG. 4 is a rear elevation thereof; and

FIG. 5 is a top plan view thereof.

Patent	Priority	Assignee	Title
D271136,	Oct 23 1981	TEKNAR, INC	Ultrasonic ocular biometry unit
D316144,	Feb 12 1988	Canon Kabushiki Kaisha	Refractometer
D325782,	Jan 13 1989	Essilor International (Compagnie General d'optique)	Lens testing instrument
D327326,	Jan 13 1989	Essilor International (Compagnie General d'optique)	Lens centering instrument

Patent	Priority	Assignee	Title
3602580,
3778164,
4105302,	Jun 23 1976		Automatic refraction apparatus and method
207675,
210417,
D244483,	Apr 04 1975	Nerthus, Inc.	Optical refraction testing instrument
D246188,	Sep 13 1976	CAMBRIDGE INSTRUMENTS INC , A DE CORP ; CAMBRIDGE INSTRUMENTS INC , A DEL CORP	Ophthalmometer or similar article

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Executed on	Assignor	Assignee	Conveyance	Frame	Reel	Doc
Jul 08 1977		American Optical Corporation	(assignment on the face of the patent)
May 13 1982	AMERICAN OPTICAL CORPORATION,	WARNER LAMBERT COMPANY, A CORP OF DEL	ASSIGNMENT OF ASSIGNORS INTEREST	004034	0681	pdf
May 14 1982	Warner Lambert Company	WARNER LAMBERT TECHNOLOGIES, INC , A CORP OF TX	ASSIGNMENT OF ASSIGNORS INTEREST	004034	0700	pdf
Apr 07 1988	WARNER LAMBERT TECHNOLOGIES, INC	CAMBRIDGE INSTRUMENTS INC , A DE CORP	ASSIGNMENT OF ASSIGNORS INTEREST	004893	0097	pdf

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