| 摘要 |
950,477. Screw-cutting lathes. P. F. DE VALLIERE. Nov. 17, 1960 [Nov. 20, 1959], No. 39569/60. Heading B3T. A screw-cutting lathe has a carriage 1, Fig. 1, driven by lead-screw 3, the nut 2 for which is rotatable and controlled by a cam 15 through feeler 13 for correcting pitch errors. The cam is formed of flexible strips 16, Fig. 3, and may be adjusted by jack members bearing on a bar 19 fixed parallel to the carriage guides. A cylindrical drum 9, Fig. 1, driven in unison with the lead-screw is engraved with a spiral which may be sighted through a microscope device 11, 12, fixed to the carriage, to obtain the true carriage position. The drum may be dispensed with and the spiral engraved on the tops of the threads of the lead-screw. An automatic optical control system is referred to. |
