Vane encoder assembly for adjusting an optical encoder in a data storage device

US4697077A · kind A · utility

Assignee

• Computer Optical Products, Inc. · US

Inventors

• Otto Weber · Wolfsburg, DE
• Sang S. Rhee · Calabasas, US

Key dates

• Filing date: May 12, 1986
• Grant date: Sep 29, 1987
• Expiry date: May 12, 2006

Classification

• Technology area (CPC G): Physics
• CPC primary: G01D5/34715
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Accurate gap adjustments in an optical encoder used in a magnetic disk drive are achieved within a vane encoder assembly which incorporates a four-bar linkage. The optical encoder includes a fixed reticle and movable vane disposed between a light source and light detector. The fixed reticle is coupled indirectly to a housing which has a prismatic cavity defined therethrough. The prismatic cavity is characterized by a prismatic axis which is generally perpendicular to the direction of gap adjustment between the reticle and movable vane of the optical encoder. The prismatic cavity further defines four generally parallel hinge lines within the housing in a direction parallel to the prismatic axis of the cavity. A single adjustment screw is coupled to the housing to apply a compressive force to the housing in the direction of the gap adjustment. The exertion of varying amounts of compressive force causes the four-bar linkage defined by the cavity to flex, thereby causing the upper and lower surfaces of the housing to move toward or away from each other in a plano-parallel fashion. As the upper and lower surfaces of the housing move in a plano-parallel fashion, the fixed reticle which i…