Patent GB-367722-A (GB)
Title: Improvements in multi-spindle lathes operating on bar stock
IPC: B23B9/06
Filed: 1931-08-06
Abstract: 367,722. Combined turning and drilling machines. SCHAERER, 0., 64, Friedengasse, Basle, Switzerland. Aug. 6, 1931, No. 22329. Convention date, Aug. 8, 1930. [Class 83 (iii).] In a multi-spindle turret lathe operating on bar stock, the spindles are vertically arranged and are rotated at high speed whereby the stock automatically centres itself under centripetal force so as to avoid chattering and to permit the stock to be fed by gravity through the chucks. The main driving electric motor 2 drives through a shaft 3, change gears 3a, shaft 4, and bevel gears 6, a vertical shaft 7 which through gearing 8 drives vertical workspindles 10 which are mounted in an indexible work-turret 9. The shaft 3 also drives a shaft 11 connected by worm gearing 11a to a control shaft 12. The shaft 11 drives a worm wheel 14 which is loosely mounted on a shaft 13 but may be clutched thereto by a splined coupling member 18 which is normally spring-pressed into engaged position and is disengaged by a lever 17 actuated by a cam 16 on the control shaft 12. Change gears 19 connect the shaft 13 to a shaft 21 carrying a splined clutch member 22 operable by a hand-lever 26 and controlling the drive of a sleeve 23 carrying a bevel gear 24 connected through bevel gearing 33 with a series of three radial shafts 31, which operate the tool feed mechanism associated with the various work spindles. This gearing may also be manually operated from a hand crank 29 connected to the sleeve 23. Each of the six work-spindles coacts with a pair of tools one, such as the boring tool x, having a vertical feed movement, and the other, such as a form-turning tool y being fed horizontally. For feeding the tools each radial shaft drives a cam shaft 32 carrying cams 37, 38, 37a, 38a which actuate pivoted arms 40, 41, carrying adjustable pivot blocks 42. These blocks are connected through levers 42b, 43b, and links 67a to the horizontal tools and through levers 42a, 43a to the carriers 43 of the vertical tools, these carriers being guided in adjustable guide members 46. The workturret is mounted in a headstock 47 mounted on the pillars 45 above the tools and is carried on a ball bearing 49. A dividing-plate 48 on the turret has recesses 50 coacting with a locking bolt 51 which is withdrawn for indexing the turret by means of a segment 51a operated through a lever 51c from a cam on the control shaft 12. After withdrawal of the bolt, indexing is performed by a pin 53 coacting with Geneva slots 52 in the dividing-plate and carried on a lever secured to a stock-feed control shaft 55 which is rotated intermittently by the control shaft 12 through gears 56. The shaft 55 carries a cam-drum 58 imparting vertical movement to an enclosing sleeve 59. The stop 65 for determining the feed of the stock is also actuated by lever mechanism 64 from the shaft 55. Each work spindle, Fig. 6, comprises a tube 72 having at its lower end a bevelled surface 72a operating a split collet 79a which grips the work bar z and is connected to a collet tube 71. A sleeve 69 secured to the tube 72 serves as a guide for a chuck-actuating sleeve 68a coacting with fingers 70 which are mounted in slots in the sleeve 69 and are suspended from an annular seating 73. When the sleeve 68a is moved downwardly, the fingers 70 are released and move outwards by centrifugal force and thus allow a sleeve 74 secured to the collet tube 71 to move downwards and unclamp the work. Pins 75 are fitted in bores in the head of the sleeve 74 and bear at one end against the tube 72 and at the other against a ring 77 located in a sleeve 76 secured to the sleeve 74. The ring 77 is slotted to guide exchangeable brake shoes 78 so that during the downward feed movement of the stock bar the brake shoes are moved by a surface 77b into engagement with the stock bar to prevent shock during the gravity feed. The sleeve 68 is actuated at the feeding station by a projection 60 on the camactuated sleeve 59. In order to impart intermittent movement to the control shaft 12, the worm 12a carries coupling teeth 80 coacting with teeth on a splined coupling member 80a which has a cam surface coacting with a spring bolt 81 controlled by a slider 82 actuated by a projection 33a on the wheel 33. When the slider is actuated, the bolt 81 is withdrawn from the position shown in Fig. 10a and the sleeve 80a then descends and the shaft 12 is driven through one revolution whereupon the sleeve 80a is again raised through its cam surface 80b. The tools x may consist of roughing and finishing drills and reamers and the tools y of roughing, finish-turning, and cutting-off tools. The tools x may be rotated in a direction opposite to the work-rotation:by toothed gearing 86 between the shaft 7 and the tool spindles 67. For screwing, the tools may be driven at different speeds for running on and off the work by means of gears 92a, 92b, the gears being selectively engaged by a clutch member 92 actuated by a cam 90 on the oscillating shaft carrying the work stop 65. The cycle of operations for the production of a hubshaped work-piece is described in the Specification. If only a small number of tooling stations is required to finish a work-piece the machine may be equipped with duplicate feed mechanism arranged diametrically opposite the feed control shaft 55. In this way two pieces may be completed at each revolution of the work-turret. Cuttings, catching and removing.-The rotary shaft 7 may be fitted with a shield 87 which by centrifugal force directs outwardly any cuttings which fall towards the centre of the machine.