| 摘要 |
867,936. Milling-machines. CINCINNATI MILLING MACHINE CO. Dec. 24, 1959 [Jan. 7, 1959], No. 43857/59. Class 83 (3). A machine tool comprises means 33 for applying an upward pressure to a verticallymovable member 15 to more than counterbalance its weight and means for applying an equal downward pressure on the member when it is desired to move the member downwardly. Thd cutter slide 15 is adjustable vertically by a hand-crank 20 rotating a nut 24. The work is carried on a slide 12. The counter-balancing device comprises a piston 33 and a hollow rod 30 connected to the slide. When the crank 20 is rotated to lower the slide, the pressure beneath the piston 33 is increased, due to the line 47, Fig. 2, being connected to a resistance 46. The pressure drop across the resistance causes a valve 49 to be actuated to connect the pressure line 45 to the upper end of the piston 33. In a second embodiment, the resistance is constituted by a restricted bore in a modification of the valve 49. |
