Scanning system of a position measuring device

Abstract

A scanning system of a position measuring device for photo-electric scanning of a measuring graduation, the scanning system including a support carrying measuring components, an adapter including a scanning graduation in a graduation plane and a holder that holds the support on the adapter. The holder is structured so that the support is stationarily positioned on the adapter in six degrees of freedom, but compensates thermally caused expansion of the support in relation to the adapter in a first coordinate direction and a second direction which define the graduation plane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of an embodiment of a position measuring device with a scanning system designed in accordance with the present invention;

FIG. 2 shows a perspective view of an embodiment of an adapter with a scanning graduation to be used with the scanning system in accordance with FIG. 1 in accordance with the present invention;

FIG. 3 represents a partial sectional view of the scanning system in accordance with FIG. 1; and

FIG. 4 shows an embodiment of a rod-shaped solid state joint to be used with the scanning system of FIG. 1 in accordance with the present invention.

Claims

1. A scanning system of a position measuring device for photo-electric scanning of a measuring graduation, the scanning system comprising: a support carrying measuring components;an adapter comprising a scanning graduation in a graduation plane; anda holder that holds said support on said adapter, wherein said holder is structured so that said support is stationarily positioned on said adapter in six degrees of freedom, but compensates thermally caused expansion of said support in relation to said adapter in a first coordinate direction and a second direction which define said graduation plane.

2. The scanning system in accordance with claim 1, wherein said holder compensates thermally caused expansion of said support relative to said adapter in a third coordinate direction perpendicularly with respect to said graduation plane.

3. The scanning system in accordance with claim 1, wherein said holder comprises a spatial arrangement of solid state joints.

4. The scanning system in accordance with claim 3, wherein each of said solid state joints are rod-shaped and are rigid along longitudinal axes of said joints, but can be deflected in directions perpendicular thereto.

5. The scanning system in accordance with claim 4, wherein each of said solid state joints have two bending sections extending in said respective longitudinal axis, said two bending sections are separated from each other by a non-bendable section.

6. The scanning system in accordance with claim 5, wherein each of said two bending sections has a round cross section.

7. The scanning system in accordance with claim 5, wherein at least one of said solid state joints extends in one of said first coordinate direction, said second coordinate direction and a third coordinate direction perpendicular to said first and second coordinate directions, and wherein said at least one of said solid state joints maintains said support rigidly on said adapter in said one of said first coordinate direction, said second coordinate direction and said third coordinate direction, but keeps said support deflectable in two other ones of said first coordinate direction, said second coordinate direction and said third coordinate direction.

8. The scanning system in accordance with claim 1, wherein said adapter is made of a material with a negligible coefficient of expansion.

9. The scanning system in accordance with claim 9, wherein said material is a glass-ceramic material.

10. The scanning system in accordance with claim 1, wherein said measuring components comprise optical components.

11. The scanning system in accordance with claim 10, wherein said optical components are lenses.

12. The scanning system in accordance with claim 1, wherein said measuring components comprise electrical components.

13. The scanning system in accordance with claim 12, wherein said electrical components of said support are detector elements.

14. The scanning system in accordance with claim 1, wherein said support is arranged in a recess of said adapter.

15. The scanning system in accordance with claim 10, wherein said support constitutes an enclosed receptacle, in whose interior said optical components are arranged.

16. The scanning system in accordance with claim 12, wherein said support constitutes an enclosed receptacle, in whose interior said electrical components are arranged.

17. A position measuring device comprising: a measuring graduation; anda scanning system for photoelectrically scanning said measuring graduation, said scanning system comprising:a support carrying measuring components;an adapter comprising a scanning graduation in a graduation plane; anda holder that holds said support on said adapter, wherein said holder is structured so that said support is stationarily positioned on said adapter in six degrees of freedom, but compensates thermally caused expansion of said support in relation to said adapter in a first coordinate direction and a second direction which define said graduation plane.