| 摘要 |
1,077,118. Boring and milling machines. GIDDINGS & LEWIS MACHINE TOOL CO. Aug. 4, 1965 [Aug. 4, 1964], No. 33294/65. Headings B3B and B3C. [Also in Division F2] In a large machine tool (Fig. 1, not shown) comprising a headstock (25) movable vertically on a column (23) mounted on a column base (24) which is movable horizontally on a base (22) by a reversible drive unit (20), the drive unit comprises a reversible hydraulic motor (29) driving four output pinions (45-48), which mesh with a common rack (30) secured to the base (22), through reduction gearing wherein each pinion is driven through a separate planetary stage (Figs. 10, 11, not shown), the planetary stages being interconnected in pairs to balance the powers transmitted by the output pinions (see Division F2). The gearing is torsionally preloaded to obviate backlash and to increase damping of torsional vibration. A spring applied disc brake (116) holds the gearing while the motor (29) is inoperative, and is released hydraulically when the motor is energized, by fluid pressure from the motor supply line. |
