| 摘要 |
739,020. Variable - speed gearing ; operating clutches. AMMCO TOOLS, Inc. Aug. 26, 1953 [Sept. 30, 1952], No. 23448/53. Class 80 (2). [Also in Group XXII] The work spindle 38 of a lathe has axial feed motion imparted to it by rotation in a threaded part of the frame of a lead screw 44 driven from the spindle 38 through variable - speed epicyclic gearing housed in a casing 276 moving axially with the spindle and screw, the gearing comprising a side gear 329 which is loose on a spindle 324 fixed in casing 276, is geared to a disc 291 fixed on spindle 38, and meshes with planet pinions 342 carried by a sleeve 338 to which is secured a gear 352 engaging a gear 420 connected to screw 44 through a claw clutch 406, 410, the pinions 342 in turn meshing with a side gear 346 loose on sleeve 338. Gear 346 meshes with a gear 366 rigid with a disc 364 which frictionally engages between conical surfaces of disc 291 and a disc 295 urged axially towards disc 291 by a spring comprising oppositely-arranged conical spring discs 308 such as to exert substantially constant pressure throughout the full range of movement of disc 295. Disc 364 and gear 366 are carried by one end of a control lever 356 pivoted on spindle 324, the other end of the lever carrying a pin 380 engaging a helical groove 378 in a spindle 270, so that, by turning the latter by means of a dial knob 388, the degree of penetration of the disc 364 between the discs 291, 295, and thus the speed of gear 352, may be varied. Since the loading of spring 308 is substantially constant, slip can occur between disc 364 and discs 291, 295 upon the occurrence of a predetermined resistance, irrespective of the setting of lever 356. The screw 44 may be rotated manually, after disengagement of the claw clutch 406, 410, by means of a hand wheel secured to a shaft 434 connected to the screw by bevel gears 426, 436. The claw clutch is controlled by a manuallyoperable handle 452 secured to the upper end of a shifted shaft 442, but is disengaged automatically when the cutting operation is completed by a rod 456, one end of which is connected to the handle 452 by a pin 454 while its other end has adjustably secured thereto a collar which comes up against a fixed stop. |
