Patent ID: 7552544
Filing Date: 2009-06-30
Classification: G01B

Abstract:
1. A digital displacement measuring instrument, comprising: a body; a spindle slidably provided on the body; and an encoder that detects displacement of the spindle, wherein the encoder comprises a rotor that rotates in a circumferential direction of the spindle and a stator that is fixed on the body being spaced apart from the rotor by a predetermined gap, wherein the rotor is supported by a rotor bushing comprising an engaging key engageable with a key groove axially provided on an external circumference of the spindle in a manner that the gap between the rotor and the stator is kept constant, wherein the rotor bushing comprises a rotor bushing restrictor that prevents the rotor bushing from moving in a direction away from the stator along the axial direction of the spindle, and wherein the rotor bushing restrictor comprises: a fixing member fixed on the body; and a rotor bushing attitude retainer placed between the rotor bushing and the fixing member to be contacted with both of the rotor bushing and the fixing member to keep the rotor bushing in an attitude substantially perpendicular to the axis of the spindle.