Patent GB-352446-A (GB)
Title: Improvements in and relating to multiple-spindle automatic lathes
IPC: B23B9/02
Filed: 1930-01-31
Abstract: 352,446. Lathes. GERSTADT, A., 5, Goslarer Platz, Charlottenburg, Berlin. Jan. 31, 1930, No. 3392. Convention date, Jan. 31, 1929. [Class 83 (iii).] A multiple spindle automatic lathe has a central tool slide which is provided with a polygonal tool holding portion 8 and is controlled by two cams for the working and idle strokes respectively, the cams being driven intermittently by separate but interconnected drives and the movement of one cam being arrested during the movement of the other. The control cams for various parts of the machine are arranged on a number of separate shafts, this arrangement permitting the central space of the machine bed to remain free for the passage of chips. The under frame comprises a cuttings tray 1 which supports a bed 2 carrying the work turret housing 3 and gear box 4, these parts being connected by a bridge-piece 5 and by a hollow central shaft 6. The central tool slide 8 slides on the shaft 6 and moves along guides 9 on the bed to prevent rotation. The machine is driven from a motor 17 mounted on a bracket 16 and driving a pulley 14 on a main driving shaft 40. Side tool slides 10 .. 13 and 20 are actuated by cam shafts 18, 19 arranged at the front and back of the machine respectively, the shaft 18 having cams 21, 220, 210 and the shaft 19, cams 22, 222 for actuating the respective tool slides through lever mechanism. The central tool slide is actuated by two cam drums 29, 30, arranged on a shaft 26 and rotated intermittently by separate interconnected drives, the cam drum 29 effecting the working movement of the central slide and the drum 30 the idle movement. The cam 29 actuates a slide 31 carrying an adjustable rack 32 engaging a pinion 33 meshing with a rack 34 on the tool slide. The cam 30 actuates a slide 35 carrying the pinion 33. The pinion 33 is centrally arranged between the guides 9 so that it imparts a direct thrust to the tool slide. During the working movement, the cam 30 and slide 35 are stationary so that any movement of the slide 31 to the right by the cam 29 moves the tool slide to the left by the same amount. When the cam 29 reaches its highest point and the tool slide is moved fully to the left, the slide 31 engages a stop and the cam 30 commences to rotate, thus shifting the slide 35 to the right. The pinion 33 now rolls on the stationary rack 32 and moves the tool slide to the right by an amount equal to twice the movement of the slide 35. This doubling of the return movement enables the size of the cams 29, 30 to be reduced and permits a higher speed of operation. During the second half of the revolution of the cam 30 the slide 35 is moved back to the left thereby first moving the rack 32 to the left until it re-engages the low portion of the cam 29 and then giving the quick approach movement to the tool slide. At this point the cam 29 is again rotated to start a fresh working movement of the tool slide. The cam 29 is driven from an auxiliary shaft 80 through a clutch 96, bevel gearing 95, and worm gearing 27. The cam 30, which is loose on the shaft 26 is also driven at high speed from the shaft 80 through a clutch disc 101 and gears 100, 97. The intermittent movements of the two cams are controlled by a cam disc 103 mounted on the cam shaft 19. At a predetermined point, the cam 103 acts through a lever 104 to engage the clutch 101 and impart a one revolution movement to the cam 30. During the rotation of the cam 30 the cam 29 may be stopped by the disengagement of the clutch 96 by a cam 98 driven by the wheel 97 and loosely mounted on the cam shaft 19. The cam 98 also restarts the movement of the cam 29. The cam shafts 18, 19 are driven simultaneously with the cam 29 and at the same speed by worm gearing from the cross shaft 28. The shaft 40 passes centrally through the support 6 and drives the work spindles through gears 41, 43 and the drilling and screw cutting adjuncts through gears 46, 47 and shaft 48. The shaft 40 is connected by a chain 125 and gear train 119, 120, 121 to a shaft 111 for the high-speed operation and through a change gear train 117, 116, 114, 113, 112 for the working operations. The high and low gears are selectively engaged at the required times in the cycle by means of a clutch 110 operated by a cam 122 controlled from a cam 124 on the cam shaft 19. The shaft 111 is coupled to the shaft 80 through a gear 106 which has two sets of clutch teeth so that the shaft 80 may be coupled either to the power drive or to bevel gearing 107 for hand operation. The work turret indexing, stock feed, and stock clamping are derived from the shaft 80. For indexing the work turret a tappet wheel 78 coacts with a pawl disc 76 controlled from a cam 131 and actuating a pinion 75. The stock feeding and clamping cam 88 is similarly driven through a gear train 85 from a pawl 83 controlled by a cam 130. The cam shaft 89 also carries a cam 91 which may be arranged to actuate other auxiliary devices. A cam 81 on the shaft 74 may be arranged to act through lever mechanism 212, 213, 214 to withdraw the side too] slides positively before the feed movement begins. The Specification as open to inspection under Sect. 91 (3) (a) describes also means for indexing the work turret 44. For this purpose the pinion 75 engages wheels 72, 73 connected by a crank pin 71 which reciprocates a rack 69, Fig. 9 (Cancelled), and rotates the work turret through a one-way drive 65 and toothed ring 64. The turret is locked by a bolt 55, Fig. 7 (Cancelled), acting in conjunction with a stop pawl 53. The bolt is operated by cam discs 600, 63 the former serving to withdraw the bolt through the lever 60 and the latter acting to force the bolt positively inwards through a lever 62 after the indexing movement. A brake band 50 assists in holding the work turret in position, the tightening of the band being effected by a cam 59 acting through a push rod 57 and lever 56. The central tool slide and bridge 5 are provided with oil channels to admit lubricating liquid to the tools of the central and side slides. The bed 2 is perforated in the middle portion to allow discharge of the cuttings, a longitudinal channel being formed through the bed from which the cuttings are fed by a conveyer to a chamber m. The under frame is divided by partition walls into several compartments a .. d, f, g, i, k, with interposed openings covered by screens. The oil flows in the manner shown by arrows in Fig. 14 (Cancelled) and is finally returned to a suction reservoir d. Cleaning holes are provided at rand s. This subject-matter does not appear in the Specification as accepted.