Angled strut diaphragm spring

• US 4,840,457 A
• Filed: 12/17/1987
• Issued: 06/20/1989
• Est. Priority Date: 12/17/1987
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: General Electric Company
• Inventors: Remer, James N.
• Primary Examiner(s): Arnold, Bruce Y.
• Assistant Examiner(s): Ben, Loha
• Application Number:
  US07/134,121
• Time in Patent Office: 551 Days
• Field of Search: 350/255, 350/247, 369/44, 369/45, 369/46
• US Class Current: 359/824
• CPC Class Codes: G11B 7/0932 Details of sprung supports

Abstract

The inability of the lens of an optical disc recorder to focus rapidly may be the salient factor limiting the data transducing rate. In order to provide smooth motion of the focus head and to maximize its speed, a focus lens assembly for an optical disc recorder is resiliently supported by one or more diaphragm springs, and is driven by a magnetic-coil arrangement to focus light onto the optical disc. Each diaphragm spring includes inner and outer support regions connected by a plurality of resilient support arms. Each support arm has straight, parallel sides and extends nonradially.

Claims

1. An arrangement supporting a lens relative to a frame for providing motion normal to a flat surface of a disc storage medium, comprising:

a lens arrangement adapted for motion in a direction along a lens axis and normal to said flat surface of said disc;

at least one thin, flat support means, said support means including a first circular support region fixed to the periphery of said lens arrangement, said first circular support region having a diameter, said support means further including a second circular support region mechanically affixed to said frame, said second circular support region having a diameter greater than said diameter of said first circular support region and being coaxial therewith, said support means further comprising a plurality of elongated arms extending between and interconnecting said first and second circular support regions of said support means, each of said elongated arms having substantially straight, parallel first and second elongated sides, one end of said first elongated side of each arm joining said first circular support region at a respective reference radial from said axis, and a second end of said first elongated side joining said second circular support region at a respective second radial angularly displaced from said reference radial in one angular direction, one end of said second elongated side of each arm joining said first circular support region at a respective third radial displaced from said reference radial in an angular direction opposite to said one angular direction, the other end of said second elongated side extending to join said second circular support region at a point within the arc subtended by said reference and second radials.

2. An arrangement according to claim 1 wherein said lens arrangement comprises a flange mechanically coupled to said first circular support region of said support means.

3. An arrangement according to claim 2 wherein said second circular support region of said support means is adapted to be clamped between mating faces of flanges of said frame.

4. An arrangement according to claim 1 wherein said plurality of elongated arms are defined by triangle-like cutout portions.

5. An arrangement according to claim 1 wherein said support means is formed from a sheet of beryllium copper.

6. An arrangement according to claim 5 wherein said sheet of beryllium copper is less than 0.005 inch thick

7. A support for a focus lens in a disc recorder for allowing said lens to move normal to a surface of a disc referenced to a support frame, said support comprising:

a thin, flat, inner support portion in the form of an annulus centered on an axis, said inner support portion being adapted to be mechanically coupled to said lens;

a thin, flat, circular outer support portion, said outer support portion being adapted to be coupled to said support frame, said outer support portion further being larger in diameter than said inner support portion and concentric therewith, said outer support portion being substantially coplanar with said inner support portion when said support is in an undeflected state; and

a plurality of thin, flat arms joining said inner and outer support portions, each of said arms including first and second substantially straight parallel sides, said sides of said each of said arms extending between said inner and outer support portions along non-radial lines relative to said axis in such a fashion that any radial line originating at said axis which passes through one of said arms passes through at least one of said sides of said one arm.

8. A support according to claim 7 wherein each of said first and second sides of each of said arms includes first and second ends, and wherein said first end of said first side of one of said arms intersects said inner support portion at a reference radial and said second end of said first side of said one arm intersects said outer support portion at a second radial angularly displaced in a first direction from said reference radial, and said first end of said second side of said one arm intersects said outer support portion at a third radial displaced in said first direction from said second radial, and said second end of said second side of said one arm intersects said inner support portion at a fourth radial lying within the acute angle included between said reference and second radials.

9. A support for a movable piece for allowing said piece to move parallel to an axis, said support comprising:

a thin, flat inner support portion in the form of an annulus centered on said axis, said inner support portion being adapted to be mechanically coupled to said piece;

a thin, flat, circular outer support portion, said outer support portion being adapted to be coupled to said support frame, said outer support portion further being larger in diameter than said inner support portion and concentric therewith, said outer support portion being substantially coplanar with said inner support portion when said support is in an undeflected state; and

a plurality of thin, flat arms joining said inner and outer support portions, each of said arms including first and second straight parallel sides, said sides of said each of said arms extending between said inner and outer support portions along substantially straight, non-radial lines relative to said axis in such a fashion that any radial line originating at said axis which passes through one of said arms passes through at least one of said sides of said one arm.

10. An arrangement pursuant to claim 9 further comprising electromagnetic drive means for driving said movable piece in the direction of said axis.