Patent GB-1101292-A (GB)
Title: Multiple-spindle automatic lathes
IPC: B23Q5/14
Filed: 1966-01-13
Abstract: 1,101,292. Variable-ratio gearing. WERKZEUGMASCHINENFABRIK GILDEMEISTER & CO. A.G. 13 Jan., 1966 [13 Jan., 1965], No. 1679/66. Heading F2D. [Also in Division B3] In a multi-spindle automatic lathe having an indexable spindle drum 2 and piston-operated chucks, the spindles 3 are driven by a drive mechanism comprising first and second power trains enabling individual spindles to be driven at different speeds and direction, and further comprising cam-operated speed selector devices and devices for stopping each spindle in a predetermined angular rotational position. The first power train comprises a motor M1, beltdriven change gears 9, 10, 11 and a drive shaft 12 leading from in front of the spindle drum 2 to drive the spindles 3 through a central gear 13, spindle gears 4 and clutches 5. The second power train comprises a motor M2 belt-driven change gears 16, 17, 18 and a drive shaft 19 leading from the rear of the spindle drum 2 to drive the spindles 3 through a central gear 20, spindle gears 4a and clutches 5a. Brakes 23 are provided on each spindle 3. Fixed cams and cam holders 39 actuate slides 30, 30a which in turn axially move switching sleeves 34, 35 to operate the clutches to select the spindle speed when the spindle drum 2 is indexed. Single tooth clutches 37 are also provided to stop the spindles in a predetermined angular position. In Fig. 3 (not shown), the single tooth clutch is engaged by a pressure cylinder (54) and piston (55) device which moves a shoe (40), the slide 30a and the switching sleeve 34 towards a fixed component of the clutch on a supporting plate 27. A chain drive (45), (46) encircling all the spindles 3, drives at a crawling speed through gears (44), (43) and the gear (38) formed on the switching sleeve 35, the spindle 3 until the clutch components 37 engage. At this point further movement of the switching sleeve 35 by the piston 55 disconnects the chain drive by means of abutting faces (53), (52) operating on a pivot arm (49) to move gear (43) out of engagement with gear (38) on the switching sleeve. In a modification (Figs. 4 and 5, not shown) the single tooth clutch for positioning the spindle is engaged automatically when the spindle drum is indexed by incorporating in the fixed cam a spring-biased cam (68) and, after the switching sleeve 35a has moved to disengage the driving clutch 5 and the spindle has been braked, the switching sleeve 35a is further moved axially to engage friction surfaces (58), (63). As the friction surface (58) is being driven at a crawling speed by a chain drive (59), (60), the spindle (3) is rotated until the single tooth clutch engages. At this point the spring-biased cam (68) moves the switching sleeve 35a to completely engage the clutch and simultaneously, abutting faces (65), (67) act to disconnect the chain drive to the spindle 3 at the friction surfaces (58), (63). In order to change spindle speed whilst a workpiece is being machined, a device (Fig. 6, not shown) comprising links (73) and a pivoted lever (72) and operated by a piston and cylinder (55), (54) arrangement serves to disconnect one driving clutch 5 and immediately engage the other driving clutch 5a. The change gears 9, 10, 11 or 16, 17, 18 may be replaced by steplessly adjustable gearing for constant cutting speed for face work.