Angular encoder

• US 5,771,594 A
• Filed: 07/22/1996
• Issued: 06/30/1998
• Est. Priority Date: 08/05/1995
• Status: Expired due to Term

• Current Assignee: Dr. Johannes Heidenhain GmbH
• Original Assignee: Dr Johannes Heidenhain GmbH
• Inventors: Feichtinger, Kurt
• Primary Examiner(s): Will, Thomas B.
• Application Number:
  US08/681,053
• Time in Patent Office: 708 Days
• Field of Search: 33/1 PT, 33/1 N, 33/706, 33/707, 33/708, 33/572, 250/231.13, 250/231.14, 250/231.18
• US Class Current: 33/1.0PT
• CPC Class Codes: G01D 11/02 Bearings or suspensions for moving parts
• CPC Class Codes: G01D 5/34738 Axles; Driving or coupling means

Abstract

An angular encoder for determining an angular position between a stationary element and an element rotatable relative to the stationary element and including a coupling for connecting a scanning unit with a stationary element and formed of a spring material, with the coupling having at least two plates which extend transverse to each other and one of which extends parallel to a rotational axis of the rotatable element, and with each of the two plates having a plurality of leaf spring arms which are so formed and aligned that the leaf spring arms extend in directions of their respective application lines in which directions forces are applied to the coupling during rotation of the rotatable element relative to the stationary element.

Claims

1. An angular encoder for determining an angular position between a stationary element and an element rotatable relative to the stationary element, the angular encoder comprising:

a measuring standard associated with the relatively rotatable element;

a scanning unit for scanning the measuring standard;

and

a coupling for connecting the scanning unit with the stationary element without a possibility of the scanning unit being twisted with respect to the stationary element but with a possibility of displacement of the scanning unit in radial and axial directions;

wherein the coupling is formed of a spring material and has at least two plates which extend transverse to each other by, one of which extends parallel to a rotational axis of the rotatable element and the other extends transverse to the rotational axis and of the rotatable element, and

wherein each of the at least two plates has a plurality of leaf spring arms which are so formed and aligned that the leaf spring arms extend in directions of respective application lines thereof in which directions forces are applied to the coupling during rotation of the rotatable element relative to the stationary element.

2. An angular encoder as set forth in claim 1, wherein the outer contours of the leaf spring arms extend substantially parallel to the respective application lines.

3. An angular encoder as set forth in claim 1, wherein the coupling is formed as a one-piece part.

4. An angular encoder as set forth in claim 1, wherein the coupling comprises a plurality of plates extending parallel to each other and forming a parallel guide, the plates, which extend parallel to each other, extend substantially parallel to the rotational axis of the rotatable element and are connected with each other by the plate extending transverse to the rotational axis.

5. An angular encoder as set forth in claim 4, wherein the coupling has two plates extending parallel to each other and parallel to the rotational axis of the rotatable element, wherein the two parallel plates are connected, at respective one ends thereof, to one of the scanning unit and the stationary element and are connected at respective ends thereof, which are opposite to the one ends, with the plate, which extends transverse to the rotational axis of the rotatable element, and wherein the transversely extending plate is connected in diametrically opposite regions thereof to the other one of the stationary element and the scanning unit.

6. An angular encoder as set forth in claim 4, wherein the coupling has four plates which extend parallel to the rotational axis of the rotatable element and which form two spring parallelograms extending perpendicular to each other, wherein respective one ends of the four plates are connected with the plate, which extends transverse to the rotational axis of the rotatable element, and wherein other respective ends of two opposite plates extending parallel to each other are connected to the scanning unit, and respective other ends of two other opposite plates extending parallel to each other are connected to the stationary element.

7. An angular encoder as set forth in claim 1, wherein the leaf spring arms of the plate, which extends parallel to the rotational axis of the rotatable element form a triangle, wherein a side of the triangle is connected at a free end thereof to one of the stationary element and the scanning unit, and wherein an apex of the triangle, which is located opposite the side connected to the one of the scanning unit and the stationary element, is located at least in a vicinity of a connection region of the parallel plate with the other plate which extends transverse to the rotational axis of the rotatable element.

8. An angular encoder as set forth in claim 7, wherein the transversely extending plate is formed of four leaf spring arms forming a quadrangle, and wherein two of the four leaf spring arms are connected, in an apex region of the triangle, with the two leaf spring arms of the parallel plate.