摘要 |
A micrometer includes: a body; a fixed sleeve that is fixed to the body; a spindle that is screwed to the fixed sleeve; 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. Ball bearings are disposed between the thimble and the operation sleeve.
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