Improvements in Feed Mechanism for Capstan or Turret Lathes.

摘要

25,704. Smith, A. H. Nov. 5. Lathes; chuckcs.-Stock, in a hollow spindle lathe, is fed by an intermittently - advanced carrier connected by a ratchet or like device to a bar reciprocated in one direction by a spring and in the other direction by gearing from the spindle. A stop determines the precise amount of feed, and the mechanism is controlled by the chuck-operating mechanism, which is of the type described in Specification 15,744/08. The collet 26, Fig. 1, is drawn into a bevelled socket 27 to grip the stock by a cam-sleeve 28 engaging a mating-cam on the spindle 22 and rotated by inclined slots 31 in a sleeve splined to the spindle and traversed by a hand-lever 35. A ball thrust bearing is interposed at 37. The hand lever slides a boss 34 on a fixed tube 2, which guides a rack-bar 3 connected to the stock carrier 8 by a pawl 6. Motion of the bars to open the chuck advances a cam bar 39, Fig. 9, to trip a catch 12 and release the bar 3. A spring 4 then effects the feed as limited by an adjustable screw stop 47. At the same time, a second bar carried by the boss is advanced into a recess in a quadrant plate 23 and maintains it in the position shown in Fig. 9. When the boss is returned to close the chuck, this bar is removed and the quadrant is rocked by a spring 24, to engage a worm 15 driven from the spindle at 21, Fig. 1, with teeth 14 on the bar 3. On the completion of the return movement, the catch 12 snaps into place and a projection 42 disengages the worm 15. According to the Provisional Specification, the worm 15 is driven through spur gearing, and the quadrant plate is rocked by a bell-crank operated by the boss 34; and, in a further modification, a continuously-rotating screw driven from the main spindle is employed in connexion with a half - nut carried by a pivoted rocker to effect the return of the bar 3.