Geometrical instruments – Miscellaneous – Light direction
Patent
1993-11-29
1995-04-25
Fulton, Christopher
Geometrical instruments
Miscellaneous
Light direction
33568, 33DIG3, 108137, 108143, 248913, 269 71, B23Q 1600, G01B 500
Patent
active
054087503
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE ART
The present invention relates to an X-Y table apparatus which moves articles to be loaded in an X-Y plane with respect to a base, and more particular to an X-Y table apparatus provided with an X-Y encoder for being capable of accurately detecting displacements in two-dimensional directions.
Background of the Art
X-Y tables each for setting an article to be loaded, such as a work to be measured or machined, at a required position are widely used in various machines such as measuring machines, tool machines and the like.
In general, the X-Y table of this type is provided with a stable base, an X-directional moving member movable in the X-direction with respect to the base, and a Y-directional moving member (or a mounting member) movable in the Y-direction with respect to the X-directional moving member. To detect displacements, in the X direction and Y direction, of an article loaded on the mounting member, linear encoders for detecting the displacements are provided on the adjacent two sides (directed in the X direction and the Y direction, respectively) of the mounting member.
In the conventional X-Y table of general type, however, the linear encoders must be fixed to the outer surfaces of the mounting member. This renders the outer dimensions of the apparatus large. Further, protecting covers are required for protecting the encoders, which are extremely precise equipment, from dust and/or external shocks, because otherwise the encoders are exposed to the outer atmosphere. Two separate encoders must be used for the two axes, leading to a high manufacturing cost and requiring complicated wiring. Further, the article on the mounting member is displaced from the linear encoders. Thus, there has been a problem that a small distortion and/or play of the table directly gives adverse effects to the measuring accuracies.
Disclosure of the Invention
The present invention was made to solve the problems of the prior art and its object is to provide an X-Y table which has a simple and small structure and provides improved measuring accuracies.
First, in order to achieve the object, the present invention provides an X-Y table characterized by comprising a base, an X-directional moving member which is movable in the X direction with respect to the base, a mounting member which is movable in the Y direction with respect to the X-directional moving member and on which an article is loaded, and displacement detecting means for detecting displacements of the mounting member with respect to the base, the displacement detecting means including a main scale having a first matrix-shaped land lattice cooperatively provided on the center of the rear face of the mounting member and an index scale provided in parallel with the base so as to be movable in two-dimensional directions with respect to the main scale and having an orthogonally crossing second lattice and an orthogonally crossing third lattice.
Secondly, the present invention is to provide an X-Y table characterized in that the first lattice comprises a reflection type land lattice, the orthogonally crossing second lattice of transparent type is provided on the central portion of the index scale, the third lattice of transparent type is provided on the outer peripheral portion of the second lattice, a light emitting element is provided on the rear face of the orthogonally crossing second lattice of transparent type, and light receiving elements are provided on the rear face of the third lattice of transparent type.
With the X-Y table according to the present invention, the displacements of the mounting member (loaded article) in the X and Y directions are detected by a single displacement detecting means, leading to the miniaturization and a low manufacturing cost of the table. Further, as the displacement detecting means can be disposed substantially on the central portion of the mounting member, the measuring accuracies can be improved.
The X-Y encoder which is now being considered has a main scale and an index scale disposed opposed to each othe
REFERENCES:
patent: 4575942 (1986-03-01), Moriyama
patent: 4676649 (1987-06-01), Phillips
patent: 4953965 (1990-09-01), Iwase et al.
patent: 5065092 (1991-11-01), Sigler
patent: 5123174 (1992-06-01), Noguchi
patent: 5142791 (1992-09-01), Kobayashi et al.
John T. Winthrop et al.; "Theory of Fresnel Images. I. Plane Periodic Objects in Monochromatic Light"; Journal of the Optical Society of America, vol. 55, No. 4; Apr. 1965; pp. 373-381.
Ishibashi Wataru
Teng Hongchun
Fulton Christopher
Mitutoyo Corporation
LandOfFree
X-Y table apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with X-Y table apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and X-Y table apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1559984