Flexure hinge

Patent metadata

Field	Value
Publication number	US-9964142-B2
Application number	US-201715610471-A
Country	US
Kind code	B2
Filing date	May 31, 2017
Priority date	Jun 1, 2016
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A flexure hinge with two material segments connected to each other via a material tapering to a thin spot which defines a pivot axis between the two material segments. The material segments are provided with recesses such that the strength existing in the thin spot with respect to normal stresses or bending stresses is kept largely constant within a distance from the thin spot.

First claim

The invention claimed is:

1. A flexure hinge comprising:
(a) a first material segment and a second material segment monolithically connected together along a thin spot which defines an imaginary pivot axis between the first material segment and the second material segment, at least one of the first material segment and the second material segment having a thickness along a direction X which tapers in a tapering zone along a direction Y perpendicular to the direction X to a minimal thin spot thickness, the imaginary pivot axis extending in a direction Z perpendicular to the direction X and the direction Y;
(b) at least one recess positioned in the tapering zone of the at least one of the first material segment and the second material segment; and
(c) wherein the at least one recess is formed so that a plane defined by the direction X and the direction Z passing through the at least one recess intersects the respective material segment to define cross section areas spaced apart along the direction Z and comprising geometric shapes the width of which along the direction Z decrease with increasing distance along the direction Y from the position of the thin spot along the direction Y.

2. The flexure hinge of claim 1 wherein the cross section areas defined at a given direction X and direction Z plane passing through the at least one recess together provide a strength that corresponds, within tolerances, to the strength provided by the cross section area defined by the intersection of a direction X and direction Z plane passing through the thin spot.

3. The flexure hinge of claim 1 wherein the at least one recess is formed such that along at least a portion of the length of the at least one recess along the direction Y, the cross section areas define a constant total area regardless of the point along the direction Y at which the given direction X and direction Z plane intersects the at least one recess.

4. The flexure hinge of claim 3 wherein the constant total area is equal to the area defined by the intersection of the direction X and direction Z plane through the thin spot.

5. The flexure hinge of claim 1 wherein along at least a portion of the length of the at least one recess along the direction Y, a moment of resistance about the imaginary pivot axis remains constant.

6. The flexure hinge of claim 1 wherein the cross section of the thin spot defined by the intersection of the direction X and direction Z plane at the thin spot has the shape of one or more rectangles.

7. The flexure hinge of claim 1 wherein the cross section areas spaced apart along the direction Z comprise a plurality of identical geometric shapes.

8. The flexure hinge of claim 1 wherein the at least one recess has an outline in a direction Y and direction Z plane in which:
(a) two boundary lines extend away from the thin spot along the direction Y from a common vertex which comprises the part of the at least one recess lying closest to the thin spot; and
(b) where one or both boundary lines depart from a plane defined by the direction X and direction Y plane lying at the vertex, the departure being symmetric along a curve with increasing distance from the thin spot along the direction Y.

9. The flexure hinge of claim 8 wherein a segment of the curve is formed in dependence on the material thickness of the tapering zone given at the respective position along the direction Y.

10. The flexure hinge of claim 1 including multiple recesses identical in shape and lying side by side along the direction Z.

11. The flexure hinge of claim 1 wherein one or more recesses are provided along the direction Y in each of the first material segment and the second material segment on both sides of the thin spot.

12. The flexure hinge of claim 11 wherein the first material segment and the second material segment each include a respective tapering zone and at least one recess is provided in each tapering zone and wherein each recess is positioned in the same distance from the thin spot along the direction Y.

13. The flexure hinge of claim 1 wherein that the thin spot is divided by at least one opening into a plurality of thin spot segments that lie side by side in the direction Z.

14. A measurement apparatus comprising the flexure hinge of claim 1 wherein the flexure hinge is part of a lever, a coupling rod, a rotating hinge, a free flex pivot hinge, or a parallel arm mechanism.

15. A method for producing a flexure hinge according to claim 1 wherein the at least one recess is introduced into the tapering zone at least in part with a laser applied on both sides of a direction Y and direction Z plane lying at the imaginary pivot axis.

Assignees

• Wipotec Gmbh

Inventors

• Rübel Andreas
• Bur Christian

Classifications

• B23K26/384

  of specially shaped holes · CPC title

• F16C11/12 Primary

  incorporating flexible connections, e.g. leaf springs · CPC title

• E05D1/02

  made of one piece · CPC title

• B23K26/0619

  with spots located on opposed surfaces of the workpiece · CPC title

• G01G21/07 Primary

  of flexure-plate bearings · CPC title