Patent ID: 8296966

Claim:
A micrometer comprising: a body; a fixed sleeve that is fixed to the body; a spindle that is screwed to the fixed sleeve and is axially advanced and retracted; a thimble that is rotatably fitted to an outer circumference of the fixed sleeve and has an outer end connected to the spindle; an operation sleeve fitted over a range from an outer circumference of the thimble to an outer end of the spindle and being rotatable relative to the thimble; and a constant pressure mechanism that is disposed between the operation sleeve and the spindle, the constant pressure mechanism transmitting a rotation of the operation sleeve to the spindle and allowing a free rotation of the operation sleeve against the spindle when a predetermined or more amount of load is applied on the spindle, wherein a bearing member is disposed between the thimble and the operation sleeve, and the bearing member is provided by a rolling bearing.