| 摘要 |
1,150,393. Tool slides. WARNER & SWASEY CO. 2 Jan., 1968 [5 Jan., 1967], No. 250/68. Headings B3B and B3T. [Also in Division F2] In a machine tool such as a lathe, having a tool-carrying slide which is mounted on the bed for movement in a path inclined to the vertical and in which drive means is provided for moving the slide in the inclined path, mechanical braking means is provided to prevent downward movement of the slide due to self weight when the machine is inoperative and the magnetic brake inactive. The slide 24 carries a tool turret 13 and moves transversely of the lathe spindle 11 and is driven by motor (35), Fig. 3 (not shown), via a shaft 33 on an extension of which is a ball screw 31 which rotates with the shaft to effect movement of the slide. The mechanical brake 50 is connected to the shaft 33 and includes arcuate brake members 53, 54 with brake shoes 51, 52 which continuously engage an annular brake drum 70 mounted on the outer sleeve of a roller type overrunning clutch (75), Figs. 4, 6 and 7 (not shown), on the shaft 33. The action of the clutch permits free rotation of the shaft during upward movement of the slide but facilitates wedging engagement between the shaft and the clutch sleeve during downward movement of the slide so that, any movement in the downward direction causes the brake drum to rotate with the shaft and thus a continuous resistance to this direction of movement is provided by the brake shoes acting on the drum 70. This driving resistance is normally overcome by the drive motor but when the motor is inoperative the brake resistance is sufficient to prevent any downward movement of the slide due to its own weight. |
