Patent GB-302996-A (GB)
Title: Improvements in or relating to multiple spindle metal cutting and like machine tools
IPC: B23B39/16
Filed: 1928-09-28
Abstract: 302,996. Orbel, C. G. Dec, 24, 1927, [Convention date]. Drilling-machines ; tapping.-A multiplespindle metal-cutting machine has a workholder mounted on a slide movable to and from the tool-spindles and indexable transversely in order to present the work to each spindle in turn. As applied to a drilling and tapping machine a bed 1 carries a headstock 2 in which are journaled a drilling-spindle 14, Fig. 5, and a tapping-spindle 12. A stepped pulley 7, Figs. 4 and 5. drives a shaft 8 carrying two gears 9, 10 of different size, the gear 9 engaging a gear 11 freely rotatable on the tapping-spindle 12 and the gear 10 engaging a gear 13 pinned to the drill-spindle 14, the two tool spindles being in a horizontal plane. The work-holder comprises a bracket 46, Figs. 2, 4 and 5, vertically adjustable by bolts and slots on a vertical projection 45 of the carriage 4 which is slidable to and from the tool-spindles on an extension 3 of the headstock by means of a rack bar 40 secured to the carriage and a pinion 42 operated from a hand capstan 43 through gearing. The bracket 46 carries a trunnion 50 on which the work-holder 51 is capable of rocking between the limits imposed by screws 49 in lateral extensions 48 of the bracket co-acting with a stop 52 on the holder. The holder may be adapted to the particular work upcn which the machine is desired to operate, and for producing tapped holes in the ends of engine connecting-rods, radial with respect to the gudgeon pin holes, an interchangeable pin 53 is provided for engagement with the gudgeon pin hole. The work-holder is moved to the right as in Fig. 2 for drilling the hole and to the left for the tapping operation, the cutting feed being applied by the capstan 43. A ball thrust bearing 38, Fig. 5, is provided for the drilling-spindle 14. The tapping-spindle 12 Figs. 4 and 5, is slidable and rotatable in the oppositely rotating gears 11, 15, the former being driven directly from the gear 9 and the latter from the gear 13. Dogs 16, 17 on the gears 11, 15 respectively are adapted to engage similar dogs 18, 19 on a coupling 20 secured to the spindle when the latter is moved axially by the thrust of the work on the tap. During tapping the dogs 16, 18 are engaged to rotate the tap slowly and when the work is withdrawn a spring 37 assists in disengaging the dogs 16, 18 and engaging the dogs 17, 19 for a rapid reverse rotation. The coupling 20 comprises a hollow casing 22, Figs. 5 and 6, freely mounted on the spindle and enclosing a disc 25 pinned to the spindle. Annular flanges 26, 27 on the disc enclose four rubber segments 30 through which the drive is transmitted from keys 23 pinned in recesses in the casing 22 to keys 31 secured to the disc 25. A cover-plate 32 which carries the dogs 19, engages the casing 22 by shallow projections engaging recesses 24, Fig. 6. The annular flange 27 is cut away at 28 to permit some rotational movement of the keys 23 relatively to the disc 25. Jigs.-A bracket 55, Figs. 2 and 5, adjustable on the carriage 4 by means of a slot and bolts 56, carries an interchangeable guide bush 57 for the drill.