Patent GB-744296-A (GB)
Title: Single spindle automatic turret lathe
IPC: B23B11/00
Filed: 1952-06-11
Abstract: 744,296. Turret lathes. WORRELL, G. July 20, 1953 [June 11, 1952], No. 14751/52. Class 83 (3). A single spindle automatic turret lathe comprises a number of fixed headstock-stations concentric with the axis of the turret, the spindle being located at one such station, and the same number of turret stations also concentric with the turret axis, the stations. in each set being equi-angularly disposed and at equal distances from the turret axis whereby each of the turret stations coincides with a headstock station for all rotational settings of the turret. The bed of the machine is fabricated by welding from steel plate of different thicknesses and one such plate 11, Fig. 1, supports the front bearing 37 for the hollow spindle 1 which carries an autoatically-operated collet 39. This plate also carries the front bearing for the turret 63 and, concentric therewith, a number of fixed tool stations H2, H3, H4, Fig. 10, carrying drills, rosebits or reamers. Rotary tool spindles. These tool stations operate on a workpiece after it has been severed from the stock bar and transferred to an auxiliary rotating- spindle 274, Fig. 13, at one of the turret stations. A further live-spindle is provided on the turret for screwing or tapping, and both spindles are driven from the shaft 1 through changespeed gearing to a hollow shaft 106 which has a splined connection with a shaft 62 passing alongthe turret axis. The splined connection allows for the turret traverse in feeding the turret-tools or the work in the auxiliary spindle against the stationary-headstock tools. The auxiliary turret spindle 274 is driven from shaft 62 by an intermediate gear 79, Fig. 13. Screwing &c. is effected by a die-head fixed to the second turret rotary spindle and a projection on the spindle-casing engages a fork 205, Fig. 1, which operates a multiple switch 207 for controlling solenoid-operated clutches to change the die-head spindle from a " slower than the main spindle " speed for screwing to a " faster than the main spindle " speed.for retracting the die-head. Thus the work is screwed by a differential action without altering the main spindle speed. The other auxiliary turret spindle, which grips the work during parting-off and then carries it in a second cycle around to the stationary headstock tools, has its collet operated through a lever 94, Fig. 1, by a catch 97 and a cam piece (not shown), the former being moved by a lever 101 controlled by a cam 103 integral with the main turret-feeding camdrum 57. The collet 39 on the main spindle is controlled through linkage 58 and a cam 55 on the inside of the same cam-drum. The main spindle 1 is driven by belts 26, 27 and an electric motor 25, the belt pulleys 28 being expanded and contracted by moving their axis through a screw and nut device 35, 36, to vary the spindle speed. Lever tool-rests.-A pair of lever tool-rests 142, 143, Fig. 10, carrying parting and form tools respectively, are carried on pivots 144, 145 supported in the framework. The tools are fed against the resistance of springs 156 by cams 149, 164, operating through levers and adjustable connections, the screw adjusters 160 extending outside the machine frame for convenience. The cams for feeding the tool-rest are carried by overhead shafts geared to a main overhead shaft 59 which drives, at a slow speed, the main cam drum 57 through a chain and sprockets 132-134. The shaft 59 is driven by reduction gearing from the main spindle and a clutch is interposed in the drive to enable the shaft to be turned by hand for setting up the machine. Turret indexing and locking mechanism.- Dogs 192, Fig. 15, on the main cam-drum 57 engage recesses in a wheel 190 to give stepwise movement to the turret through gearing 189, 188. The turret has four stations and the workpiece shown requires two complete turret revolutions to complete a new workpiece while the other is held in the auxiliary turret spindle. A disc 168 secured to the turret-spindle is provided with four peripheral index slots 167 which, as the turret is fed forward, engage the edges of two long, fixed, location-bars 169, 170, Fig. 16, arranged on each side of the turret axis. When the turret is withdrawn the disc 168 is moved clear of the locking-bars and is then free to be indexed, and a locating member 182 is moved by a lever 185 and campieces 183 integral with the dogs 192 to locate the turret in its new setting prior to moving into the range of the locking bars. The completed work in the auxiliary spindle is ejected therethrough when a fresh workpiece is taken up by this spindle immediately prior to parting off from the main stock as referred to above. Stop for stock feed.-A stock stop may be carried at one of the turret stations to limit the feed of the stock through the spindle 1.