| 摘要 |
690,075. Drilling. TRIGGS, W. W. (Niles-Bement-Pond Co.). April 27, 1951, No. 9883/51. Class 83 (iii). A machine-tool comprises a movable work-table 32 carrying an elongated bar 40 of magnetic material having integral equallyspaced projections on one side, electric indicating means 74 for indicating the position of an electric head 44 relatively to a projection, and precision means 62, 64 to move the head predetermined distances in a direction parallel to the bar. The precision drilling-machine described has -a spindle 18 driven by a motor 20 and movable vertically by hand or powers in an adjustable carriage 16. The work-table 32 is movable by hand or by a motor 34 on a slide 26 which is itself movable by hand or a motor 28 on a base 10. The spacing of the projections on the bar 40 is preferably a multiple or fraction of an inch. The electric head 44 comprises two spaced inductance coils 46 surrounding polepieces 48 in a magnetic circuit similar to that described in Specification 607,702. The electric head 44 is resiliently attached to a sliding block 60 which abuts against the screwed member 62 which is used to set the head 44 in a zero position relatively to a micrometer dial 68 on the screw 64 which engages a fixed nut 66. After initial adjustment the dial 68 and member 62 are locked together by a clamp 72. Similar positioning means may be provided on the slide 26. |
