Patent GB-190107810-A (GB)
Title: Improvements in Lathes.
Inventor: HARTNESS JAMES
Filed: 1901-04-16
Granted: 1902-04-16
Abstract: 7810. Hartness, J. April 16. Lathes; tool-holders; screwing.-Relates to a turret lathe, chiefly for operating on bar stock, but applicable also to face work. The various parts, with the exception of the chuck spindle, are operated by fluid pressure, preferably air, which, in the case of feed movements, may act through a liquid controlled by a meter. The lathe may be operated automatically, semi-automatically, or by hand. The hollow spindle 210, Fig. 1, is driven at a slow speed by a pulley 216 acting through back gear, and at a quicker speed by a pulley 215, a loose pulley 214 being placed between. These pulleys may be driven from a countershaft 224 coupled to a shaft 499, Fig. 1<a>, in a hollow standard 497. The shaft 499 and a second shaft 500 have cone pulleys for varying the speed of the lathe, the shaft 500 being driven in either direction by oppositely-moving belts 511, 512, controlled by forks 513, 514, pivoted at 515 and having pins 517 engaging slots 518 in clips 520 on a rod 521, moved automatically or by hand. Both belts are shown on loose pulleys, the belt 511 being shifted on to a fast pulley by moving the rod to the left and the belt 512 being moved on to fast pulley by a movement to the right. The top of the standard is hollow to serve as a guide for the stock. The belt on the cone pulleys is shifted by forks on front and back rods 525 (only one being shown), each connected to a lever 528. One lever is secured on a shaft 530, and the other is pivoted on the shaft and connected by a spring to an arm 531 fast on the shaft. A handle 534, loose on the shaft, has a lug 535 which engages either the fast lever 528 or the arm 531 when the handle is moved in one direction or the other. This arrangement causes one of the rods 525 to be directly moved to shift the belt down on one side, while the other rod is yieldingly moved through the spring to shift the belt up on the other side, when the handle is moved in either direction. The turret slide 202 is reciprocated by a piston and rod in a cylinder 235 shown diagrammatically in Fig. 83, the rod engaging a lug 238 on the slide. A multiple-way plug valve 240 can be operated by hand to admit air from a supply pipe 287 to a pipe 286 leading to the cylinder or to a pipe 283 leading to a tank containing liquid. If the opening of the valve is considerable, the liquid has a free passage through pipes 284, 285 from the tank to the cylinder or vice versÔ, thus allowing the slide to move rapidly in the corresponding direction to withdraw the turret or bring it up to the work. By reducing the opening of the valve a bye-pass connecting the pipes 284, 285 is closed and the liquid passes through pipes 294, 295 to and from a meter 288, thus obtaining a slow and regulated feed. The meter comprises a loose piston in a cylinder to which liquid is admitted by a D-slide operated by an eccentric and belt 301 from the chuck spindle. The movement of the piston determines the amount of liquid passedat each stroke, and is regulated by a screw at one end of the cylinder and a cam-operated stop at the other. The turret is rotated at the rear end of its stroke by a barbed rod 231 on it engaging spring latches 233 on a bar 234 adjustable on the bed. A cutting-off tool 241, Fig. 2, independent of the turret, is carried by an arm pivoted on a shaft 243 supported above the bed. The front end of the arm is connected by an adjustable rod 248 to a piston-rod 247 working in a cylinder 251. The arm is normally raised by a weight 255, but can be depressed by admitting air above the piston in the cylinder 251 by a valve 258. The tool then moves rapidly toward the work till the piston covers an aperture in the cylinder. Liquid in the lower end of the cylinder is then compelled to escape through a small adjustable aperture into a receptable 2581, thus regulating the cutting speed of the tool. When the air is exhausted at the end of the cutting-stroke, the weight 255 raises the tool and arm, the liquid returning freely to the cylinder through a pipe 262 and check valve. Mechanism for receiving and removing the finished product comprises a holder 303, Fig. 35, pivoted on an arm 305 carried by a sleeve 306 on the shaft 243, and normally occupying the position shown in full lines. The turret operates a ratchet-wheel at the back of the lathe at each reciprocation, the wheel having the same number of teeth as there are tools in the turret, and carrying a cam which, after each cycle of oparations, causes a horizontal rack shaft 325, Fig. 2, to operate a vertical rack 315 engaging a pinion on the sleeve 306, and thus rock the holder under the work 307 as it is cut off. The parts are returned by a spring, and the work tipped out by the engagement of a finger 308 on the holder with an arm 309. After each article is cut off, the stock is fed by a roller feed of ordinary construction, including a ratchet-wheel 348, Fig. 1, which can be held by a spring pin 349 to allow the feed to take place. The pin is operated by a rod attached to the yoke which opens the chuck. The yoke is operated by an air cylinder controlled by a threeway valve 366. Fig. 39 shows a form of toolholder for use on the turret. A casing 537 to which is pivoted a holder 540 carrying a tool 543, has an aperture to pass over the work. The holder is mounted on a spindle 542 carrying an arm 543 on which is pivoted a lever 544, depressed by a bar 268 to rock the tool inwards by the engagement of the eccentric boss of the lever with a screw 546 in the casing. The parts are returned by a spring 547. The casing is provided with sliding V-blocks 549, 550, which bear against the work to take the thrust of the tool. The blocks are held in place by screws 556 and a yoke 555 with leaf springs to hold the parts together. Fig. 30 shows a form of holder in which the tool and V-block 559 are brought into operation together by the bar 268, which acts on a sliding wedge 561 with a curved slot in which a pin 564 on the tool-holder 563 travels. For producing taper or irregular work, a bar 268 is used which imparts a slow radial movement to the tool as the turret is traversed. The bar 268 is carried by arms 265, 267, Figs. 1 and 2, on the shaft 243 and operated by a piston in a singleended cylinder 277 through a rod 273, the cylinder being controlled by a valve. This valve and the valves 240, 258, 366 are operated automatically by a cam shaft 390 rotated intermittently by an independent motor when the various controlling devices or escapements permit. The motor comprises two cylinders 393, Figs. 1 and 74, with single-acting pistons 395 which operate arms 397 carrying pawls engaging ratchet-wheels on the shaft, the arms and pistons being returned by springs 400. Air is admitted or exhausted by valves 396 with tappets 401 on the rods, operated by the arms 397. The air pressure is insufficient to cause damage when the cam shaft is locked. A cam-wheel 404 on the shaft operates the valve 240 automatically except the movement necessary to close the bye-pass to give a slow feed to the slide. The lower end of the valve plug has a loose arm which may be locked to the plug, a pin on it then projecting into the path of cams angularly adjustable round the wheel 404. These cams operate the valve to obtain a rapid movement of the turret in either direction. The bye-pass is closed at different times for different tools by a yoke on a rocking table supported in the bed, the table carrying adjustable notched bars, one for each tool in the turret. These bars are adapted to be engaged by corresponding spring pins carried by the slide, the rotation of the turret releasing a pin corresponding to the tool to be used. The engagement of a pin and bar rocks the table and operates the valve to advance the slide at the regulated speed. A similar cam-wheel 403 operates the valve 258, and a third cam-wheel 405 operates the valve 366 and that of the cylinder 277. There are three escapements to hold the cam shaft 390, and to regulate the time and amount of its rotation. The first escapement is controlled by the movements of the turret and slide, and consists of a perforated wheel 434 with removable pins, operated by a spider 437 having the same number of teeth as there are tools in the turret. This spider is driven by the before mentioned ratchet-wheel at the back of the lathe, and thus releases the cam shaft at each rearward movement of the turret, allowing the shaft to rotate one tooth of the spider if the other escapements permit. The second escapement is controlled by the cutting-off tool, and comprises a wheel 445 with removable pins or teeth engaged by a pawl released at the desired time by a dog 454 on the piston-rod 247, which disengages the pawl by means of a lever and sliding pin. The third escapement is controlled by the " knock-off " mechanism, and the stop for regulating the feed of the stock. It comprises a wheel 455 similar to the wheel 415, and engaged by a pawl which is released by a pin actuated by a cam lever. This lever is actuated by the engagement of a pawl on the turret corresponding to the tool in use with a corresponding notched bar adjustably secured on the bed, and thus releases the cam shaft to allow it to stop the advance of the slide. This escapement is also actuated by the feed of the stock, by means of a spring finger 491, Fig. 35, on an arm 490 on the sleeve 306, the finger bearing against the work when the holder 303 is swung forward, and springing into the path of the advancing stock when the work is cut off. The engagement cf the stock with the finger displaces the sleeve longitudinally to actuate the said cam lever and release the cam shaft to effect the closing of the chuck. To vary the speed of the slide while operating on the work, a disc 494 with adjustable screws acts on a pin to vary the travel of the loose piston in the meter. When a screwing-die is used on the turret, it may be closed by the bar 268 acti