Patent GB-621756-A (GB)
Title: Improvements in lathes
IPC: B23Q15/00
Filed: 1946-08-13
Abstract: 621,756. Lathes. JONES & LAMSON MACHINE CO. Aug. 13, 1946, No. 24031. Convention date, Aug. 14, 1945. [Class 83 (iii)] [Also in Groups XXIV and XXXVII] A lathe comprises a headstock, a turret mounted on a ram 6 and automatically indexed on the retraction of the ram, a slow feed means for the ram with a knock-off actuated by the ram at a point preselected for each turret position, means for moving the ram at a fast idle speed in each direction with an electrical means for changing from fast idle speed to feed at a point in the advance preselected for each turret position, electrical means actuacted by the knock-off to retire the ram at fast speed, and electrical means actuated by the ram at its retire limit to advance the ram at fast speed. The slow feed of the ram 6, Fig. 1, is provided by a feed-rod 30, driven from the headstock as described in Specifications 448,369 or 602,822, the drive being connected in along a shaft 47, Fig. 16, which carries a pinion 52 meshing with a fixed rack 53 on the machine frame. The fast idle speed is provided by a reversible electric motor 40, Fig. 2, mounted on the ram and driving the pinion 52 through a clutch 48, actuated by solenoids 415, 343. The pinion 52 may be rotated manually by pressing a knob 60, Fig. 17, rearwardly to disengage the clutch 48 and to engage dogs 62, 63 connecting a hand wheel 64 to shaft 47. The advance limits of the ram for each turret position are determined by axiallyadjustable stops 8, Fig. 2, which actuate a knock-off mechanism 35, 32, such as that shown in Specification 448,369. The stops are carried on the ram and are indexed with the turret at the end of each stroke by means such as are shown in Specification 462,770. Similarly mounted and indexed is a selector stop mechanism 21 to control the movements of the ram and to initiate a cycle of operations of a cross-slide 75 carrying tools 76, 77. The slow-feed of the slide is also provided by the feed-rod 30, Fig. 1, which is reversed by mechanism, such as described in Specification 448,369, actuated by solenoids A24, A25. Fast idle speed is provided by an electric motor which rotates a nut 82, Fig. 21, on the slide feed-screw 80 through a reversing clutch 96 actuated by solenoids A22, A23, Figs. 1 and 2, acting through linkage 101. The selector stop mechanism 21 actuates switches 37LS, 10LS, 12LS, 6LS, Fig. 6, in an electrical system (see Group XXXVII) by means of dogs 24, adjustably mounted thereon, for an automatic cycle of operations. At the start of a cycle, the ram has moved to bring a tool towards the work and the switch 10LS is closed. A main switch is closed and a start button 310 depressed to start the motor 40 in a forward direction. The ram advances until the switch 6LS is closed by a dog 24 which changes the ram motion to slow feed. A stop 8 interrupts the slow feed and releases the lever 32 which falls and operates a switch 9LS to reverse the motor 40 after a time delay and re-engage the clutch 48. Towards the outer limit of the ram movement, the selector 21 is indexed. At the limit, a switch 4LS is opened by a stop S on the ram and the motor 40 reversed after a time delay. The cycle is completed when the switch 10LS is contacted by a dog at the first index position which stops the ram and resets the circuit for the next cycle. To skip a turret position, a dog is positioned to engage the switch 12LS, after just clearing the index position, which retires the ram at fast speed. The cross-slide cycle is started by the switch 37LS which energizes solenoid A23 to throw in the fast speed for the front tool. The slide carries its own selector stop bar 125, Fig. 13, actuating switches 27LS, 31LS, 35LS and 33LS by dogs 132. When switch 27LS is closed, the slow feed clutch solenoid A24 is energized after a time delay. The slow feed is stopped by a knock-off mechanism 121 similar to that described in Specification 497,439 and actuated by stops 122 on the slide. This allows the feedlever to fall and actuate a switch 29LS to energize the solenoid A22 and return the slide at fast speed to mid-position where it is stopped by a dog 132 actuating switches 35LS and 31LS. A second dog 24 on another face of the selector 21 trips the switch 37LS again to retire the slide. With switch 37LS and 31LS closed together, the fast speed reverse commences through solenoid A22. Feed and return fast speed follow on actuation of the switches 33LS, 29LS and 31LS. The ram and cross-slide motions are interlocked so that the slide can be started at either end of the ram travel and, if done at the beginning, both operate simultaneously. When the slide is operating, the ram stops when it opens switch 4LS and cannot continue until the slide has completed its half-cycle owing to an interlocking relay in the circuit. When the slide is nearly at its mid-position, it actuates switch 35LS to energize the relay and the ram starts forward. An emergency retire button can retire both the ram and the slide to fully retracted and midposition respectively, except when the ram is in slow feed. A switch 305, Figs. 1, 6, permits complete manual or automatic operation. When hand-feed is desired during a cycle, a dog is set to engage the switch 10LS at the end of the fast approach. The cycle is resumed by depressing a retire cycle start button 690 which acts to retire the ram and the cycle is resumed.