Patent GB-495205-A (GB)
Title: Improvements in electric chucking mechanism
IPC: B23B31/26
Filed: 1937-05-27
Abstract: 495,205. Lathes ; chucks. FAIRWEATHER, H. G. C. (National Acme Co.) May 27, 1937, No. 14779. [Class 83 (iii)] In an automatic chucking-machine having an indexable turret carrying rotating chuck spindles an electric motor is provided for rotating the chuck-operating mechanism as each spindle reaches the work-changing station and a separate electric motor is provided for axially shifting the chuck-operating means at that station. The jaws of the chucks of successive spindles P, Fig. 4, are opened and closed as described in Specification 453,332 by the engagement of lugs 40 on an axially movable shaft 30 with a nut 19 controlling a draw spindle. The shaft 30 is rotated by a motor mechanism B -controlled by a starting switch C and by switches B<1>, B<11> which give a coarse and fine adjustment respectively of the voltage applied to the motor to vary the grip of the jaws. The motor 32 of the mechanism B drives the shaft 30 through a worm wheel 38 in splined engagement therewith. The shaft 30 is shifted axially by a motor mechanism A, Fig. 8, comprising a motor 42, also controlled by the switch C, which operates, through gears 43, a rack 44. Cam slots K, L, Fig. 3, in the rack produce longitudinal movement of bars 47, 48, the rod 48 controlling the clutch O of each rotary spindle when in chucking position to stop its rotation, while the rod 47 produces axial movements of the shaft 30 by means of a member 52. The manual control switch C is normally used only for stopping the machine if the chucking has not been effected correctly, or other in. correct operation, the motor A normally being controlled to move the rack in alternate directions by respective switches D, E, Fig. 1, controlled from the cam shaft 81<1>. Switches F, G, Fig. 3, cut out the motor at either end of the movement. The motor A also controls the braking of the chuck spindle. A modification of the motor mechanism A comprises a cam disc 93, Fig. 18, driven by worm-gearing from the motor, and having cam slots L<1>, K<1> corresponding to the slots L, K, and controlling switches F<1>, G<1> performing the functions of the switches F, G. The machine goes automatically into low speed when the work spindle is stopped, and a link 60, Fig. 15, is shifted to move an arm 63 which engages a cam 64 to rock a shaft 65 through an angle. A brake 60<1> is applied to the worm shaft 60<11> of the machine to prevent coasting upon movement of the link 60, while a member 66, Fig. 10, on the shaft 65 operates the feed clutch operating lever 67. The safety lever 71, Fig. 1, is at the same time thrown from the vertical position. If the work spindle is stopped, after chucking, to rectify incorrect chucking, and has not been restarted at the point at which the machine is about to go into high speed, a cam 80 engages the yoke 67 to throw out the clutch on the feed shaft, stopping rotation of the cam shaft, and allowing time for rechucking. The machine is restarted by operation of the switch C and of the lever 83. If it is not desired to stop the machine, the lever 83 is moved to the vertical to render the cam 80 inoperative. -