| 摘要 |
<p>The micrometer measures the internal dia. of bored holes and includes a shaft (3) on the end of which is a conical ferrule (14). The ferrule has three pegs (1,2) which may be moved radially in the ferrule under the action of a rotating sleeve (8) moving along a threaded shaft. Markings (13) on the sleeve may be aligned with the graduations of one of the three scales (8,9,10) extending along the shaft. To extend the range of measurement, interchangeable heads (12) may be attached to the end of the gauge. The head has radially movable pegs (21,22) operated by the micrometer pegs, and surfaces contacting the micrometer to ensure accurate alignment. A knurled nut (18) is used to attach the additional head to the projecting bolt (15) on the end of the micrometer gauge.</p> |
